1. Rinse asparagus spears and pat completely dry with paper towels. Trim off tough woody ends by bending each spear gently until it snaps naturally, or line them up and cut off the bottom 1-2 inches.

2. Turn your Blackstone griddle to medium-high heat and let it preheat for 5-7 minutes until a drop of water sizzles and evaporates immediately.

3. In a small bowl, combine the olive oil, minced garlic, salt, pepper, and red pepper flakes if using. Stir well to combine.

4. Drizzle about half of the oil mixture directly onto the hot Blackstone surface. You can also brush the asparagus spears directly with the oil mixture.

5. Lay asparagus spears on the griddle in a single layer without crowding. Let them cook undisturbed for 2-3 minutes until bottoms develop a nice char and caramelization.

6. Use a long spatula or tongs to flip the asparagus spears to a new side. Drizzle or brush the remaining oil mixture over the top. Continue cooking for another 2-3 minutes, flipping occasionally, until asparagus is tender-crisp and charred in spots.

7. If using butter, add it to the griddle and let it melt, then roll asparagus through it to coat. Transfer to a serving platter, squeeze fresh lemon juice over the top, and sprinkle with Parmesan cheese and lemon zest if using. Serve immediately.