Chicken and Spinach Casserole

Chicken and Spinach Casserole is the ultimate comfort food that brings everyone to the table! This creamy, cheesy masterpiece combines tender rotisserie chicken, nutritious spinach, fluffy rice, and a luscious cream sauce that’ll have your family asking for seconds.

Love More Chicken Recipes? Try My Chicken Crescent Bake or this Loaded Potato Ranch Chicken Casserole next.

Why You’ll Love This Recipe

The combination of creamy sauce, melty cheese, and bright lemon creates layers of flavor. What I absolutely LOVE is how this dish sneaks in healthy spinach while still tasting indulgent and comforting. Plus, using rotisserie chicken means you can have this gorgeous meal on the table in under an hour—perfect for those busy evenings when you want something homemade but don’t have hours to spend in the kitchen. 

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Ingredient List

For the Casserole Base:

• Cooking spray
• 3 tablespoons unsalted butter
• 1½ cups chopped yellow onion
• 6 cloves garlic, thinly sliced
• 2 teaspoons dried Italian seasoning
• ¼ teaspoon crushed red pepper
• 1¾ teaspoons kosher salt (divided)
• 3 tablespoons all-purpose flour

For the Creamy Sauce:

• 2½ cups whole milk
• 4 oz chive & onion cream cheese

For the Filling:

• 4 cups shredded rotisserie chicken
• 3 cups cooked long-grain white rice
• 2 (10-ounce) packages frozen chopped spinach, thawed and squeezed dry
• 2 tablespoons fresh lemon juice
• 1 teaspoon lemon zest

For the Topping:

• 8 oz part-skim mozzarella cheese, shredded
• ¼ cup grated Parmesan cheese

Why These Ingredients Work

Okay so butter and onions are where everything starts to smell good and taste right. I tried cutting corners once and used olive oil instead of butter because I was on this health kick (that lasted approximately four days) and the whole dish tasted wrong. Like something was missing. Butter just makes things taste like food is supposed to taste—my grandma Rose used to say that and she lived to 92 so I’m taking her advice. The onions need to be yellow specifically because they get all sweet and soft when they cook down. I accidentally grabbed white onions once at Trader Joe’s because I wasn’t paying attention and they stayed sharp and kind of gross.

Six garlic cloves seems like a lot—my son Max helped me make this once and he was counting them out like “Mom are you sure that’s not too much?” but garlic gets so mellow when it cooks that you need way more than feels right or it just disappears. Later he admitted I was right but I had to promise not to embarrass him by telling his friends he admitted his mom was correct about something culinary.

The flour is basically the structural element that makes your sauce actually sauce instead of just milk with stuff floating in it. I forgot it exactly one time because I was simultaneously trying to help Harper with her ridiculous Common Core math homework and cooking and the whole thing turned into soup. Total disaster. Had to dump it and start over while my family ate cereal for dinner. Whole milk is the only option here because I tried being healthy with skim milk once and it tasted like disappointment mixed with regret. Just use the good milk. We’re eating a pound of cheese anyway so who are we kidding.

That chive & onion cream cheese was my sister Beth’s idea. She’s one of those naturally intuitive cooks who just knows what will work and I’m honestly jealous. Regular cream cheese is totally fine but the chive & onion adds this extra something that makes people tilt their heads and say “what’s in this?” in that good way.

Rotisserie chicken is hands-down the best shortcut invention of modern times. Already cooked, already seasoned, costs like $7, and you can get it literally anywhere. I tried being all fancy and cooking my own chicken breast and shredding it once to save money and it took forever, made a mess, and didn’t taste as good. Never doing that again.

Rice soaks up the sauce like a sponge which is exactly what you want. I usually make extra rice earlier in the week and keep it in the fridge for situations like this. Cold leftover rice actually works better than fresh rice because it doesn’t turn to mush when you bake it. Restaurant industry secret I learned from my friend Danny who used to work at a Chinese restaurant.

Frozen spinach is one of those ingredients that sounds boring but it’s perfect here. I tried using fresh spinach once because it seemed fancier and it wilted down to absolutely nothing and got slimy and weird in the casserole. Frozen is already cooked and chopped and you just thaw it and squeeze it out. Which brings me to the most critical thing about this entire recipe—you HAVE to squeeze all the water out of the spinach or your casserole will be a green watery swamp situation. I learned this the hard way the first time when I thought “it doesn’t look that wet” and it was very much that wet.

The lemon juice and zest are what my mother-in-law Linda calls “the secret ingredient” though I guess it’s not secret now since I’m telling the entire internet. But seriously without the lemon this is just another heavy creamy casserole that makes you want to take a nap after eating it. The lemon somehow cuts through all that richness and makes it taste bright and fresh and makes you want seconds instead of needing to unbutton your pants and lie on the couch.

Mozzarella does that cheese pull thing that looks amazing in photos and makes my kids excited to eat. Part-skim makes me feel slightly less guilty even though I know I’m lying to myself. Parmesan gets all crispy and brown on top under the broiler and adds this salty nutty flavor that makes everyone fight over the corner pieces with extra crispy cheese bits.

Essential Tools and Equipment

• 9×13-inch baking dish – I own three of these because I’m constantly making casseroles or taking food to people
• Large nonstick skillet – Where the sauce magic happens
• Whisk – Do not attempt this with a spoon unless you enjoy lumpy sauce
• Wooden spoon – My favorite stirring implement
• Kitchen towels – CRITICAL for the spinach water extraction process
• Grater – If you want to be fancy about your cheese
• Measuring cups and spoons – I eyeball most ingredients but not casserole ingredients

How To Make Chicken and Spinach Casserole

Step 1: Preheat and Prepare

Crank your oven to 350°F and move the rack up to the upper third position. Spray your baking dish really well with cooking spray—get in the corners, be generous about it. One time I was rushing and barely sprayed it and then spent half my evening after dinner scrubbing carbonized cheese off the edges while my husband watched TV. Still bitter about that.

Step 2: Sauté the Aromatics

Melt your butter in the skillet over medium heat. Once it’s all melted and starting to foam a bit, dump in the onion, garlic, Italian seasoning, crushed red pepper, and ¾ teaspoon of salt. Stir it around pretty often for about 4 minutes until the onions go from opaque to translucent—not brown, just soft and see-through-ish. This is the stage where my entire house starts smelling incredible and suddenly my kids appear from wherever they were claiming to do homework asking what’s for dinner and when will it be ready. My dog Murphy starts following me around the kitchen like something that smells that good must somehow involve him getting treats.

Step 3: Create the Roux

Sprinkle the flour over everything in the skillet and keep stirring it for about a minute. It’s going to look super weird and pasty and clumpy and you’re going to think you messed something up. You didn’t. That’s how it’s supposed to look. First time I made this I genuinely thought I’d ruined it because it looked so strange at this stage. You’re just cooking the raw flour taste out so your final sauce doesn’t taste like you’re eating paste. Don’t let it brown though—keep it blonde. If it starts getting brown your heat’s too high.

Step 4: Add the Milk

This step makes me nervous literally every single time even though I’ve done it approximately a thousand times. Pour in the milk really slowly—like painfully slowly—while you whisk constantly and I mean your arm is going to get tired but you cannot stop whisking or you will get lumps and lumpy sauce is the worst. Keep whisking for about 3 minutes until everything thickens up and stops looking like milk with flour floating around in it and starts looking like actual sauce. You’ll feel it change—it’ll start coating the whisk differently and pulling away from the pan differently. That’s your signal it’s ready.

Step 5: Stir in Cream Cheese and Seasonings

Drop the cream cheese right into your sauce along with the remaining teaspoon of salt. Keep stirring until everything melts together into this smooth creamy gorgeous situation. This is where I always “quality control taste test” which really means I want an excuse to eat a spoonful of this sauce because it’s ridiculously good. Sometimes I’ll add a tiny bit more salt here if it needs it—every batch is slightly different depending on your chicken and cheese.

Step 6: Combine All the Goodness

Pull the skillet completely off the heat. Now add your shredded chicken, rice, that extremely well-squeezed spinach, lemon juice, and lemon zest. Stir everything together until every component is coated in sauce. Should look creamy and cohesive, not like there are dry patches of rice or random chunks of chicken sitting there looking sad. I use a big wooden spoon for this and kind of fold it together like you would with cake batter.

Step 7: Transfer to Baking Dish

Scrape everything into your baking dish and spread it out relatively evenly. Use a rubber spatula to get every last bit out of the skillet because that’s where all the flavor lives and I refuse to waste it. Smooth the top down so it’s mostly flat—doesn’t need to be perfect but relatively level helps the cheese melt uniformly.

Step 8: Add Cheese and Bake

Sprinkle both cheeses all over the top. Do not be conservative about cheese. This is not the moment for restraint. Get it all the way to the edges. Put it in the oven for 15 minutes. You’ll know it’s done when it’s bubbling around the edges and the cheese has melted.

Step 9: Broil for Golden Perfection

Switch to broil and please please please do not walk away from your oven. I am begging you. Stay right there. Stare at it through the window for 2-3 minutes. Cheese goes from perfect to completely burned in approximately 30 seconds under the broiler. I have personally done this at least seven times because I thought “oh I’ll just check this text message real quick” and next thing I know there’s smoke billowing out and my smoke alarm is screaming. Pull it out the second you see nice golden brown spots.

You Must Know

That spinach water extraction process is absolutely not optional or negotiable. First time I made this I thought “it doesn’t look that wet, probably fine” and it was extremely not fine. The casserole was swimming in green water and it was genuinely disgusting. Now I wrap it in a clean dish towel and twist it over the sink until my hands legitimately hurt from squeezing and I think I’ve gotten all the water and then I squeeze it some more because there’s always more. My husband Scott walked in once while I was doing this and asked if I was okay because I was making these weird grunting sounds from the effort of squeezing.

Personal Secret: I shred my own mozzarella from a block instead of buying pre-shredded bags and I know this sounds like I’m being unnecessarily extra but there’s an actual reason. The pre-shredded stuff has anti-caking powder coating it to prevent clumping in the bag and that same powder stops it from melting smoothly. Fresh-shredded gets all gooey and stretchy and does that perfect cheese pull thing.

Pro Tips & Cooking Hacks

• Make rice the night before or that morning and refrigerate it. Cold rice doesn’t get mushy in casseroles which is a game changer. My friend Amy who’s Chinese taught me this—she says it’s the secret to good fried rice too
• When you’re adding milk don’t even think about looking at your phone or stirring something else or literally anything besides whisking that milk. Lumpy sauce is terrible and basically unfixable
• Sauce too thick? Add a splash more milk. Too thin? Let it simmer another minute
• Kitchen scissors for cutting up rotisserie chicken directly into the bowl. Saves so much time and I don’t have to wash a cutting board
• Taste the sauce before adding everything else because this is your last chance to fix seasoning
• Keep the oven door cracked during broiling so you can actually see what’s happening. My oven has a window but there’s so much glare it’s basically decorative

Flavor Variations & Suggestions

I get bored making identical food repeatedly so I experiment with this a lot:

• Mediterranean Version: Had leftover sun-dried tomatoes and artichoke hearts from pizza night once and threw them in. Used crumbled feta mixed with mozzarella. Totally different vibe, super delicious
• Southwestern Situation: My friend Rita from Houston showed me this—pepper jack instead of mozzarella, add black beans and corn, use cumin instead of Italian seasoning. Basically a different casserole but incredible
• Mushroom Addition: If mushrooms are about to go bad in my fridge I’ll slice them up and cook them with the onions. Scott goes absolutely crazy for this version
• Veggie Explosion: I’ve added bell peppers, broccoli, zucchini from the garden. Just don’t go overboard or everything gets watery
• Fresh Herb Thing: If I have basil or parsley about to turn slimy in the fridge I’ll chop it up and stir it in at the end. Tastes fresher
• Spicy: My brother puts hot sauce on everything including ice cream (gross) so when he visits I double the red pepper or add jalapeños
• Keto: My cousin Sarah’s doing keto and I made this with cauliflower rice for her. Just cook it and squeeze it bone dry like the spinach

Make-Ahead Options

This is genuinely one of my favorite features of this recipe. I can assemble everything in the morning before work, cover it with plastic wrap, stick it in the fridge, and just bake it when I get home. Let it sit out about 20 minutes while the oven heats so it’s not stone cold going in. Might need 5 extra minutes baking time since it’s been refrigerated.

Also freezes beautifully unbaked. Wrap it really well—plastic wrap then aluminum foil—keeps for months. My friend Jenny had her baby last month and I had three of these in my freezer ready to deliver. Thaw overnight in the fridge before baking. Rice freezes way better than I expected.

Recipe Notes & Baker’s Tips

• Do not skip the lemon I am serious about this. People always ask if they can leave it out because they don’t have any and no absolutely not go buy a lemon. Without lemon this is just heavy boring casserole number 4,582
• Can’t find chive & onion cream cheese? Regular with fresh chopped chives works. Or just regular, still good but less flavorful
• Tried making this with 2% milk during a health kick phase and it was disappointing. Not awful but not the same. Just use whole milk
• That bit of crushed red pepper isn’t making it spicy. Just adds background warmth you don’t consciously notice but would miss
• Turkey leftovers work amazing. I make this three times after every Thanksgiving
• Genuinely tastes better day two. Flavors meld overnight somehow

Serving Suggestions

This is basically complete by itself but I usually make salad to go with it or I feel like I’m serving beige food and my kids need identifiable vegetables. Lemon vinaigrette echoes the casserole’s citrus notes. My kids eat garlic bread with absolutely everything so that appears too.

If I’m pretending to care about health I’ll roast green beans or asparagus. Makes it feel less heavy even though we’re eating pounds of cheese. I serve it straight from the baking dish because washing extra serving dishes is pointless. Sometimes parsley on top if I’m trying to impress someone but usually skip it.

Great for having people over because you can make it hours ahead and look organized. Perfect for couch-eating-while-watching-TV nights with big bowls of warm comfort food.

How to Store Your Chicken and Spinach Casserole

Refrigerator: Stick leftovers in whatever container you have—I usually just cover the baking dish with foil if there’s not much left because why dirty another container? Keeps 4 days. Day two is actually my favorite which is weird for casseroles.

Freezer: I portion into disposable aluminum containers before freezing for easy lunch-grabbing or meal-giving. Freezes great for 3 months. Wrap really well or freezer taste ruins everything.

Reheating Instructions: Microwave single portions at 70% power for 2-3 minutes—stir halfway or you’ll have cold center hot edges situation. Whole dish needs foil cover and 350°F oven for 20-25 minutes. Frozen stuff needs overnight fridge thawing first or edges burn while middle stays frozen.

Allergy Information

Common Allergens in This Recipe:

• Dairy (milk, cream cheese, mozzarella, Parmesan)
• Gluten (flour)

Substitution Suggestions:

• Dairy-Free: My friend Rachel’s lactose intolerant and uses coconut milk plus vegan cheese. Says it’s different but still really good. Cashew cream works too apparently
• Gluten-Free: Neighbor Michelle has celiac and uses 1:1 gluten-free flour blend—says you seriously can’t tell. Cornstarch works too but only use 2 tablespoons instead of 3
• Nut-Free: Nothing with nuts here so you’re fine

Questions I Get Asked A Lot

Can I use fresh spinach instead of frozen?

Yeah but you need ridiculous amounts—like 1½ pounds because it cooks down to nothing. Blanch it 2 minutes in boiling water, drain, squeeze out every drop using kitchen towels. Fresh spinach is wetter than frozen so squeeze aggressively. Honestly I just use frozen because it’s easier cheaper and my grocery store’s always out of fresh anyway.

My sauce turned out lumpy—what did I do wrong?

Oh man been there multiple times. You have to add milk really slowly and whisk constantly without stopping even one second. Also heat can’t be too high or it cooks too fast and gets lumpy. If it happens try blending with immersion blender but honestly if it’s really lumpy sometimes easier to dump it and restart. Done that more than once.

Can I make this without rice?

Totally. Used pasta before—penne or rotini work great. Need about 3 cups cooked. Cauliflower rice works for low carb but cook it first and squeeze out moisture like spinach or soggy disaster happens.

The top of my casserole burned during broiling—help!

Broiler is absolutely brutal and I’ve burned many cheese tops. You literally cannot walk away one second. I check every 30 seconds. If your broiler runs really hot move rack lower or skip broiling altogether. Still tastes amazing just won’t have gorgeous golden top.

💬 Tried this recipe? Leave a comment and rating below! Seriously want to know everything—did you burn cheese? Did kids eat spinach? Did you add mushrooms? Tell me how it went!