In a large skillet over medium heat, add the ground turkey or chicken. Cook until browned and fully cooked, breaking it apart with a spatula, about 7-10 minutes. Drain any excess fat.

Stir in the marinara sauce, oregano, garlic powder, salt, and pepper. Let it simmer for about 5 minutes, allowing the flavors to meld.

In a mixing bowl, combine the ricotta cheese, egg, spinach, salt, and pepper. Mix until well blended.

Preheat your oven to 375°F (190°C).

In a 9x13 inch baking dish, spread a thin layer of the meat sauce on the bottom. Place 3 lasagna noodles over the sauce. Spread half of the ricotta mixture over the noodles, followed by a layer of meat sauce, and sprinkle with a third of the mozzarella cheese. Repeat the layers, finishing with noodles, remaining meat sauce, and the rest of the mozzarella and Parmesan cheese on top.

Cover the dish with aluminum foil and bake for 25 minutes. Then, remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and golden.

Allow the lasagna to cool for about 10 minutes before slicing. Garnish with fresh basil leaves if desired.