Preheat oven to 350F.

Heat a dutch oven or large skillet over medium heat and add the oil. Once it heats up, add the ground turkey, onion, garlic, salt and pepper. Cook until the meat is browned.

Add the bell pepper and stir, then add the marinara sauce and cooked noodles and mix well.

Pour half of this mixture into a 9x13 baking pan (or split between two smaller baking pans like the 7-inch round pictured above), then add the ricotta or cream cheese as well as 1 cup of the mozzarella.

Then add the remaining pasta mixture and top the casserole with the remaining 2 cups of mozzarella cheese and the parmesan cheese.

Bake for 30 minutes then broil for an additional couple of minutes for a bubbly crust if desired.