Preheat your oven to 180°C (350°F).
Cook the pasta according to package instructions until al dente.
In a skillet, sauté chopped onion and minced garlic until translucent.
Add ground meat and cook until browned.
Stir in diced bell pepper and cook for another 3 minutes.
Mix in the marinara sauce, oregano, salt, and pepper.
Combine the cooked pasta with the meat sauce mixture.
Transfer half of the pasta mixture to a baking dish.
Sprinkle half of the mozzarella cheese over the pasta.
Layer the remaining pasta and top with the rest of the mozzarella and Parmesan cheese.
Bake in the preheated oven for 25-30 minutes until cheese is bubbly and golden.