Keto Pizza Casserole: Crispy, Cheesy, and Ready in 30 Minutes

Keto Pizza Casserole is easy, irresistible, and fast comfort food! It has simple ingredients like Italian sausage, zucchini, marinara sauce, mozzarella cheese, and all your favorite pizza toppings. The best part? You can have this bubbling, melted masterpiece on your table in under 30 minutes.

Why You’ll Love This Recipe

This Keto Pizza Casserole delivers all the cheesy, meaty goodness of pizza without the carbs. Layered with flavorful sauce, melted cheese, and your favorite toppings, it’s a hearty, low-carb meal that satisfies every pizza craving guilt-free.

It tastes like real pizza. The combination of marinara sauce, melty mozzarella, crispy pepperoni, and fresh veggies hits all those pizza cravings you’ve been having. Your taste buds won’t believe it’s keto-friendly!

It’s genuinely quick. Between prep and cooking, you’re looking at less than 30 minutes (plus a quick 30-minute zucchini drain). That’s faster than ordering delivery, and infinitely more satisfying.

It’s flexible and forgiving. This recipe works beautifully in an air fryer or traditional oven, and you can customize it with your favorite pizza toppings. Pepperoni? Yes. Extra mushrooms? Absolutely. A handful of fresh basil? Go for it!

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Ingredient List

For the Base:

• 1 cup packed shredded zucchini
• 1/4 teaspoon salt
• 1/3 lb bulk Italian sausage (hot or mild, depending on your spice preference)

For the Topping:

• 1/4 cup marinara sauce (choose a low-carb variety)
• 1/2 cup shredded mozzarella cheese (about 2 ounces)
• 1/2 ounce sliced pepperoni
• 1/8 medium green pepper, thinly sliced
• 2 small mushrooms, thinly sliced

Substitution Notes: Can’t find low-carb marinara? Make your own with crushed tomatoes, garlic, olive oil, and Italian seasonings—it takes just 10 minutes on the stovetop. Prefer ground beef to sausage? Absolutely use it! Italian sausage just has those amazing seasonings built right in, which saves you a step. And feel free to swap in your favorite pizza toppings—black olives, onions, fresh spinach, or jalapeños all work beautifully.

Why These Ingredients Work

Zucchini is the secret MVP here. It creates a sturdy, pizza-like base that holds everything together while keeping the carbs incredibly low. The salt draws out excess moisture, which is crucial—it prevents your casserole from becoming a watery mess. Trust me, this step is non-negotiable!

Italian sausage brings bold, savory flavor without any extra seasoning needed. The fat content keeps everything moist and delicious, and it cooks quickly into perfectly seasoned little pieces throughout the base.

Marinara sauce gives you that authentic pizza flavor. The key is choosing a low-carb variety (aim for 5-6g carbs per serving or less)—this keeps your net carbs minimal while delivering maximum Italian flavor.

Mozzarella cheese melts beautifully and creates those gorgeous golden-brown spots you see on real pizza. It’s keto-friendly and adds richness without overpowering the other flavors.

Pepperoni, green peppers, and mushrooms are your classic pizza toppings that add texture, flavor, and visual appeal. They cook perfectly in both the air fryer and oven, staying tender while the cheese gets bubbly around them.

Essential Tools and Equipment

Here’s what you’ll want to have on hand to make this recipe smoothly:

• A small casserole dish (8×8 inches works perfectly) or two 8-ounce ceramic ramekins for individual portions
• A medium mixing bowl for combining your base ingredients
• A skillet for cooking the sausage
• A wooden spoon for breaking up the sausage as it cooks
• A slotted spoon to transfer the cooked sausage (this helps drain excess fat)
• A sharp knife for slicing peppers and mushrooms
• Measuring cups and spoons
• An air fryer (if air frying) or a regular oven

Pro tip: I highly recommend using ceramic ramekins instead of metal when making individual portions. They distribute heat more evenly and give you more control over the final result.

How To Make Keto Pizza Casserole

Step 1: Prepare the Zucchini

Shred your zucchini using a box grater or food processor. Sprinkle it generously with 1/4 teaspoon of salt and spread it out on a clean kitchen towel or paper towel-lined plate. Let it sit for 30 minutes—this is your patience-building moment, and it’s absolutely worth it! The salt draws out all that excess moisture that would otherwise make your casserole soggy.

After 30 minutes, gather up the towel and squeeze, squeeze, squeeze! Get out as much liquid as you possibly can. You want that zucchini relatively dry. Place the squeezed zucchini in a medium bowl and set it aside.

Honest note: I know 30 minutes feels like a long time, but this step is the difference between a casserole that’s perfectly textured and one that’s watery. Future you will thank present you!

Step 2: Cook the Sausage

Heat your skillet over medium heat. Add the bulk Italian sausage and use a wooden spoon to break it up into small, bite-sized pieces as it cooks. Stir occasionally and cook for about 8 minutes, until the sausage is completely cooked through and no pink remains.

Here’s my trick: keep breaking up those clumps! The smaller the pieces, the more evenly distributed the sausage is throughout your casserole. You want every bite to have that delicious sausage flavor.

Kitchen wisdom: You’ll notice fat rendering out of the sausage—that’s flavor! Use a slotted spoon to transfer the cooked sausage to your bowl with the zucchini. The slotted spoon lets the excess fat drain off, keeping your casserole from being too greasy.

Step 3: Combine the Base

Stir the cooked sausage and prepared zucchini together until well combined. This mixture is your pizza casserole foundation, and it should look lovely and cohesive.

Spread this mixture evenly in your small casserole dish (or divide between two 8-ounce ramekins if you’re making individual servings). Press it down gently so it forms a compact base layer. This helps everything hold together beautifully.

Personal note: I love making individual ramekins because they feel fancy, freeze beautifully, and you can cook them one at a time if needed. Plus, they make amazing leftovers!

Step 4: Layer Your Toppings

This is where the magic happens—and where your pizza casserole truly comes to life!

Spoon the marinara sauce evenly over your sausage-zucchini base. Don’t be shy—you want a good, generous layer, but not so much that it pools at the edges. About 1/4 cup should cover it perfectly.

Sprinkle the shredded mozzarella cheese over the sauce. Then artfully arrange your pepperoni slices, green pepper slices, and mushroom slices on top.

Step 5: Cook to Golden Perfection

For Air Fryer: Preheat your air fryer to 350°F. Place your casserole dish or ramekins inside and cook for 8 to 12 minutes, until the cheese is melted and beginning to brown. Start checking around the 8-minute mark—every air fryer is different, and you want to catch it at that perfect golden moment.

For Oven: Preheat your oven to 375°F. Place your casserole dish on the middle rack and bake for 10 to 15 minutes, until the cheese is melted and has some light browning on top.

The moment of truth: You’ll know it’s ready when the cheese is bubbly, the marinara sauce is warm and slightly thickened at the edges, and you can see just a hint of golden browning on top. That’s perfection!

You Must Know

Remove Excess Moisture from Zucchini: I cannot stress this enough—the 30-minute salt-and-drain step is absolutely critical. Without it, your casserole will be watery and underwhelming. With it, you get a beautifully textured base that actually holds its shape. This is the non-negotiable foundation of this recipe’s success.

Break Sausage Into Small Pieces: As the sausage cooks, keep breaking it up with your wooden spoon. Tiny, evenly distributed pieces mean flavor in every single bite. Large clumps of sausage will cook unevenly and won’t integrate properly with your zucchini base.

Save Some Cheese for Topping: This is my personal secret that elevates this casserole from good to restaurant-quality. That final sprinkle of cheese creates a barrier that keeps your pepperoni and veggies from drying out, and it gives you those gorgeous golden-brown spots that make people go “wow!”

Pro Tips & Cooking Hacks

Choose Your Low-Carb Marinara Carefully: Read those labels! You’re looking for a marinara or tomato sauce with no more than 5-6g carbs per serving. Many conventional brands sneak in added sugars. My favorites are brands specifically marketed as keto-friendly or low-carb. Store brands sometimes offer great options at better prices too—just check that nutrition label!

Air Fryer Timing Varies: Every air fryer has its own personality. If your model runs hot, you might be done in 8 minutes. If it runs cool, you might need 12. Start checking around the 8-minute mark and use visual cues (melted, bubbly cheese with light browning) rather than strict timing.

Use Ceramic Ramekins for Individual Portions: Metal conducts heat too aggressively and can cause uneven cooking. Ceramic ramekins give you better temperature control and more consistent, beautiful results. Plus, they look adorable on the table!

Don’t Skip the Slotted Spoon: When transferring cooked sausage, use a slotted spoon to drain off excess fat. This keeps your casserole from being greasy while still maintaining all that delicious sausage flavor.

Common Mistake to Avoid: Skipping the zucchini-draining step or not squeezing it thoroughly enough. I’ve seen it happen—the casserole gets watery, the texture suffers, and keto cravings aren’t satisfied. Don’t let this be you! Spend those 30 minutes and squeeze that zucchini like you mean it.

Flavor Variations & Suggestions

The Spicy Version: Use hot Italian sausage instead of mild, and add red pepper flakes to your marinara sauce. Feeling adventurous? Add sliced jalapeños to your toppings layer.

The Veggie-Loaded Version: Add fresh spinach, sliced olives, diced onions, or sun-dried tomatoes to your topping layer. You can increase these without significantly affecting your carb count.

The Meat-Lovers Version: Add crispy bacon bits, ground beef, or Italian seasoning-cooked ground pork along with your sausage base. Layer extra pepperoni on top for maximum pizza indulgence.

The Herb-Forward Version: Stir fresh basil into your marinara sauce, or sprinkle it on top just before serving. Add dried oregano or Italian seasoning to your sausage-zucchini base for extra depth.

The Three-Cheese Version: Mix mozzarella with ricotta and parmesan for a more complex cheese flavor. Keep the total cheese amount around 1/2 cup to maintain your macros.

Quick Customization Tip: Since you’re only making 2 servings, try different topping combinations! Make one with pepperoni and mushrooms, the other with spinach and olives. Figure out which one becomes your signature version.

Make-Ahead Options

Prepare It the Night Before: You can absolutely assemble this casserole up to 24 hours ahead! Combine your zucchini and sausage, spread it in your dish, add the sauce and toppings, cover with plastic wrap, and refrigerate. When you’re ready to cook, add about 2-3 minutes to your cooking time since it’ll be starting from cold.

Freeze for Later: This casserole freezes beautifully! Assemble it completely (but don’t cook it), cover it well with plastic wrap and then foil, and freeze for up to 3 months. Cook straight from frozen, adding about 5-7 minutes to your cooking time. It’s like having pizza casserole on demand!

Cooked Leftovers: Store leftover cooked casserole in an airtight container in the refrigerator for up to 3 days. Reheat in a 350°F oven for about 5 minutes, or in your air fryer at 350°F for 3-4 minutes, until heated through and cheese is warm.

Make Double and Freeze: Since this recipe makes 2 servings, I often make it in quadruple and freeze portions in individual ramekins. Then I have grab-and-go keto meals ready whenever I need them. Pure genius for meal prep!

Recipe Notes & Baker’s Tips

About the Zucchini: Make sure you’re packing the shredded zucchini into your measuring cup—don’t just loosely pile it in. This ensures you have the right moisture-to-base ratio.

About the Sausage: Bulk Italian sausage (the kind without casings) works best here. You’ll find it in the meat department, usually near the ground beef and ground turkey.

About Individual vs. Casserole Serving: The beauty of this recipe is its flexibility! Make it in one small casserole dish for easy sharing, or make it in two ramekins for portion control and elegant individual servings.

Temperature Matters: If your zucchini and sausage mixture is warm when you assemble it, reduce your cooking time by 1-2 minutes. If it’s cold (from refrigeration), add 2-3 minutes. Visual cues are your best friend here—cook until cheese is melted and bubbly with light browning.

About Leftovers: This casserole actually tastes amazing cold the next day if you’re into that! It also reheats beautifully and maintains its texture. Some people even enjoy it straight from the fridge as a quick snack.

Serving Suggestions

Pair with a Simple Green Salad: A crisp garden salad with lemon vinaigrette or ranch dressing is the perfect keto companion. The freshness balances the richness of the casserole beautifully.

Add a Cauliflower Rice Side: If you want to bulk up the meal, serve your casserole alongside cauliflower rice that’s been sautéed with garlic and herbs. It’s filling, low-carb, and delicious.

Serve with Garlic Bread (Modified): Make keto garlic bread using low-carb bread or cloud bread, slathered with butter, garlic, and Italian herbs. It’s the perfect vehicle for soaking up any extra marinara sauce.

Fresh Herbs on Top: Just before serving, sprinkle fresh basil, oregano, or parsley on top. It adds a pop of color and fresh flavor that elevates the whole experience.

When to Serve: This is perfect for weeknight dinners when you need something fast and satisfying. It’s also elegant enough for casual entertaining—serve it in those beautiful ramekins and your guests will be impressed!

Optional Garnishes: A tiny drizzle of quality olive oil, a sprinkle of fresh parmesan, or a few fresh basil leaves transform this from everyday to special.

How to Store Your Keto Pizza Casserole

Room Temperature: If you’re eating it fresh, it’s best served warm, right out of the oven or air fryer. Let it cool for about 2 minutes (to avoid a molten cheese situation!), and then dig in!

Refrigerator Storage: Leftover casserole keeps beautifully in an airtight container in the refrigerator for up to 3 days. The flavors actually deepen slightly as it sits, making day-two leftovers just as delicious as day one.

Freezer Storage: Store uncooked assembled casserole in the freezer for up to 3 months, or cooked casserole for up to 2 months. Wrap it well with plastic wrap and foil to prevent freezer burn.

Reheating Instructions:

• In the Oven: Preheat to 350°F, place casserole on a baking sheet, and heat for 5-7 minutes until warmed through and cheese is soft again.
• In the Air Fryer: Set to 350°F and reheat for 3-4 minutes. This method gives you the crispiest results!
• In the Microwave: Place in a microwave-safe dish and heat for 60-90 seconds. It works, but the cheese texture isn’t quite as lovely as the other methods.

Pro Tip: Reheat only the portion you’re about to eat, and keep the rest frozen. This way, your casserole stays fresher longer, and you always have a ready-to-cook keto meal waiting!

Allergy Information

Dairy: This recipe contains mozzarella cheese, which is a dairy product. If you have a dairy allergy or lactose sensitivity, you can substitute dairy-free mozzarella cheese. Brands like Miyoko’s and Violife make excellent melting varieties that perform beautifully in this recipe.

Gluten: This recipe is naturally gluten-free! The marinara sauce is your only potential concern—check the label to make sure it’s certified gluten-free or contains no questionable additives. Most pure marinara sauces are naturally gluten-free, but always verify.

Soy: Check your marinara sauce label. Some brands include soy-based thickeners or additives. There are plenty of soy-free options available, so read carefully if this is a concern.

Nightshades: Tomatoes are nightshades, so if you follow a nightshade-free diet, you’ll need to skip the marinara sauce. Some people use a creamy sauce base instead (like a garlic butter sauce with cream cheese), though this changes the flavor profile significantly.

Meat Sensitivities: This recipe contains pork (sausage and pepperoni). If you have pork sensitivities, substitute with beef sausage, ground beef, or omit the meat entirely and load up on vegetables for a vegetarian version.

Sugar-Conscious: Some commercial marinara sauces contain added sugars. Make your own or choose a brand specifically labeled low-sugar or keto-friendly to keep this recipe truly compliant with your dietary goals.

Questions I Get Asked A Lot

My casserole came out watery—what went wrong?

This almost always happens when the zucchini hasn’t been drained properly or you skipped the squeezing step. The salt draws out moisture, but you have to physically squeeze it out! Next time, really go to town—get that zucchini as dry as possible. The difference is genuinely remarkable, and you won’t regret the extra effort.

Can I make this without an air fryer?

Definitely! Use a regular oven at 375°F instead. The cooking time is similar (10-15 minutes), and you’ll get equally delicious results. In fact, the traditional oven often gives you slightly more control and more consistent golden-browning on the cheese.

How many carbs are really in this?

Per serving, this casserole contains 6.3g total carbs and 5.2g net carbs (after subtracting 1.1g of fiber). The net carbs are the number that matters for keto, making this a perfectly compliant recipe that won’t kick you out of ketosis.

Is this recipe dairy-free?

As written, no—it contains mozzarella cheese and marinara sauce. However, you can easily make a dairy-free version using dairy-free mozzarella cheese and ensuring your marinara sauce is dairy-free (most are). The texture and flavor will be slightly different, but it’s still delicious and keto-friendly!

💬 Tried this Keto Pizza Casserole? Leave a comment and rating below! I’d love to hear which variation you made—was it spicy? Veggie-loaded? Loaded with extra cheese?