Prep the zucchini “noodles”: Trim the ends and slice lengthwise into 1/8–1/4-inch planks using a mandoline or sharp knife. Lightly salt both sides and lay them on paper towels or a rack for 20–30 minutes to draw out moisture. Pat dry well.

Preheat the oven: Set to 375°F (190°C). Lightly oil a 9x13-inch baking dish or similar.

Brown the protein: Heat olive oil in a large skillet over medium. Add onion and cook 3–4 minutes until softened. Stir in garlic for 30 seconds. Add ground turkey, season with salt, pepper, and Italian seasoning, and cook until browned. If using spinach, stir it in to wilt.

Build the sauce: Pour in marinara and simmer 5–10 minutes to thicken. Taste and adjust seasoning. You want a flavorful, slightly thick sauce to avoid watery lasagna.

Mix the ricotta layer: In a bowl, combine ricotta, egg, half the Parmesan, a pinch of salt and pepper, and chopped basil or parsley. Stir until smooth.

Optional zucchini pre-cook: For the driest result, quickly grill or roast the zucchini planks for 2–3 minutes per side to release more moisture, then pat dry again. This step is optional but helpful.

Layer it up: Spoon a thin layer of sauce into the baking dish. Add a layer of zucchini planks, slightly overlapping. Spread a third of the ricotta mixture over the zucchini. Sprinkle a third of the mozzarella. Repeat layers (sauce, zucchini, ricotta, mozzarella) two more times. Finish with remaining sauce, mozzarella, and the rest of the Parmesan.

Bake: Cover loosely with foil (tent it so cheese doesn’t stick) and bake 25 minutes. Remove foil and bake another 15–20 minutes until bubbly and lightly golden on top.

Rest before slicing: Let it sit 15–20 minutes so it sets and slices cleanly. Garnish with fresh herbs and a pinch of red pepper flakes if you like.