Follow these steps to bring this comforting dish to life:

1. Preheat your oven to 375°F (190°C). Grease a large baking dish with olive oil and set aside.
2. Cook the penne pasta according to the package instructions until al dente. Drain and set aside.
3. In a large skillet, heat olive oil over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes. Stir in the minced garlic and cook for another 1 minute.
4. If using, add the ground beef or sausage to the skillet. Cook until browned, breaking it apart with a spoon, about 7-8 minutes. Drain any excess fat.
5. Stir in the marinara sauce, dried oregano, red pepper flakes, salt, and pepper. Let the sauce simmer for 10 minutes to allow the flavors to meld together.
6. In a large mixing bowl, combine the cooked pasta with the sauce, ricotta cheese, and half of the mozzarella and Parmesan cheeses. Mix until well combined.
7. Transfer the pasta mixture to the prepared baking dish. Sprinkle the remaining mozzarella and Parmesan cheeses evenly over the top.
8. Bake in the preheated oven for 25-30 minutes, or until the cheese is bubbly and golden brown.
9. Let the baked pasta cool for a few minutes. Garnish with fresh basil leaves before serving.

One of my favorite tips from Mama Lou is to let the dish rest for about 10 minutes before serving. This allows the flavors to settle and makes for perfect slices.