In a large skillet, heat 2 tablespoons of olive oil over medium heat. Sauté one finely chopped onion and 3 minced garlic cloves for about 5 minutes until fragrant and translucent.

Add 1 pound of ground turkey, cooking until browned, about 8 minutes. Stir in 28 ounces of crushed tomatoes, 15 ounces of tomato sauce, 2 tablespoons of tomato paste, 1 teaspoon of oregano, and optional red pepper flakes. Season with salt, pepper, and 1/4 cup of chopped parsley, then let simmer for 15-20 minutes, stirring occasionally.

While the sauce simmers, prepare the cheese mixture in a medium bowl. Combine 15 ounces of ricotta cheese, 1/2 cup of grated Parmesan, 1 large egg, and a handful of chopped fresh basil. Mix until smooth and well-blended.

Bring a large pot of salted water to a boil, then add 12 lasagna noodles. Cook according to package instructions until al dente, usually about 8-10 minutes. Drain the noodles and lay them flat on parchment paper or a clean kitchen towel.

Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish. Start layering by spreading a thin layer of the turkey sauce on the bottom. Place a layer of noodles over the sauce, followed by half of the cheese mixture, then sprinkle with 2 cups of shredded mozzarella cheese. Repeat the layers, finishing with mozzarella on top.

Cover the assembled lasagna with aluminum foil and bake for 30 minutes. After 30 minutes, remove the foil and bake uncovered for 15 more minutes until the cheese is golden and bubbling.

Let the lasagna rest for at least 10 minutes before slicing.