Preheat your oven to 350°F (175°C).
Boil a large pot of salted water and cook the mostaccioli until al dente.
In a large skillet, heat olive oil over medium heat.
Add chopped onion and sauté until translucent.
Stir in minced garlic and cook for an additional minute.
Add ground beef or turkey, cooking until browned.
Pour in marinara sauce, oregano, basil, salt, and pepper; simmer for 5 minutes.
Drain the cooked pasta and mix it with the sauce in the skillet.
Transfer the mixture to a baking dish and sprinkle with mozzarella cheese.
Bake for 15-20 minutes, until the cheese is melted and bubbly.