Ready to dive into cooking? Let’s make this dish step-by-step:

1. Preheat your oven to 375°F (190°C).
2. In a large skillet, brown the ground beef over medium heat until no longer pink. Drain any excess fat.
3. Add the chopped onion, bell pepper, and minced garlic to the skillet. Cook until the vegetables are soft, about 5 minutes.
4. Stir in the dried oregano, basil, and red pepper flakes. Let the spices cook for about a minute to release their flavors.
5. Add the marinara sauce and sliced pepperoni to the skillet. Stir to combine.
6. Gently fold in the cooked pasta, ensuring it’s evenly coated with the sauce mixture.
7. Transfer the mixture to a lightly greased 9×13-inch baking dish.
8. Top with shredded mozzarella and grated Parmesan cheese.
9. Bake in the preheated oven for about 20-25 minutes, or until the cheese is bubbly and golden brown.
10. Let it cool for a few minutes before serving. Enjoy!