Prepare the Zucchini "Noodles"

Slice the Zucchini: Use a mandoline or a sharp knife to slice the zucchini into thin strips, about 1/8 inch thick.

Remove Moisture: Lay the zucchini slices out on paper towels or a clean kitchen towel. Sprinkle both sides with salt and let them sit for 15-20 minutes to draw out moisture. Afterward, gently pat the slices dry with additional paper towels. This step helps prevent a watery lasagna.

Prepare the Meat Sauce

Cook the Meat: In a large skillet over medium heat, add the ground beef (or turkey) and chopped onion. Cook until the meat is browned and the onion is softened, about 5-7 minutes. Drain any excess fat.

Add Garlic and Seasonings: Stir in the minced garlic and cook for another 1 minute until fragrant. Add the marinara sauce, oregano, basil, red pepper flakes (if using), salt, and pepper. Let the sauce simmer for 10-15 minutes to allow the flavors to meld. Remove from heat.

Prepare the Cheese Mixture

Mix the Cheeses: In a medium bowl, combine the ricotta cheese, Parmesan cheese, egg, chopped parsley or basil, and a pinch of salt and pepper. Stir until well combined.

Assemble the Lasagna

Preheat Oven: Preheat your oven to 375°F (190°C).

Layer the Lasagna: In a 9x13-inch baking dish, spread a thin layer of the meat sauce on the bottom. Add a layer of zucchini slices over the sauce. Spread a layer of the ricotta mixture over the zucchini, followed by a layer of shredded mozzarella. Repeat the layers: meat sauce, zucchini, ricotta mixture, and mozzarella, finishing with a final layer of meat sauce and mozzarella on top.

Bake: Cover the lasagna with foil and bake in the preheated oven for 25-30 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden.

Rest and Serve: Let the lasagna rest for 10-15 minutes before slicing to allow it to set. Garnish with fresh basil or parsley if desired.