Cook the Ground Turkey: Heat the olive oil in a skillet over medium heat. Sauté the diced onion until soft and translucent, about 3-4 minutes. Then, add the ground turkey, season with salt and pepper, and cook until fully browned, breaking it up with a spatula as it cooks.
Make the Cottage Cheese Mixture: In a medium bowl, combine the cottage cheese, whisked egg, grated Parmesan cheese, onion powder, garlic powder, Italian seasoning, and a pinch of nutmeg. Mix until well combined.
Assemble the Lasagna: Lightly spray a 9×9-inch baking dish with olive oil and spread a thin layer of marinara sauce on the bottom to prevent sticking. Place two lasagna sheets on top, then spoon half of the cooked ground turkey mixture over them. Pour marinara sauce over top, sprinkle with mozzarella, and spread half of the cottage cheese mixture evenly.
Second Layer: Add two more lasagna sheets, pour marinara sauce over top, then layer on the remaining cooked ground turkey mixture and the remaining cottage cheese mixture. Sprinkle with mozzarella.
Final Layer: Top with the final two lasagna sheets, pour the remaining marinara sauce evenly over top, and finish with the remaining mozzarella cheese.
Bake: Cover the lasagna tightly with foil and bake at 350°F for 40 minutes. Remove the foil and bake for an additional 10 minutes, until bubbly and lightly golden on top.
Rest and Serve: Let the lasagna rest for 10-15 minutes before slicing and serving to allow it to set and to keep the layers intact.