Cook the lasagna noodles according to package directions until just tender. Drain well and set aside.

In a large skillet over medium heat, add the ground turkey or chicken. Cook until browned and fully cooked with no pink remaining, breaking it apart with a spatula, about 7 to 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, thoroughly drained spinach, salt, and pepper. Mix until well blended into a thick, creamy mixture.

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 with 3 more noodles, remaining ricotta mixture, meat sauce, and another third of mozzarella.

Add the final layer of 3 noodles, remaining meat sauce, and top with the rest of the mozzarella and all the Parmesan cheese.

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

Allow the lasagna to cool for 10 minutes before slicing. This resting time lets the layers set for clean cuts. Garnish with fresh basil leaves if desired.