Preheat oven to 375°F (190°C).
Cook cheese tortellini according to package instructions until al dente. Drain and set aside.
In a large skillet over medium heat, cook ground beef with chopped onion and minced garlic until beef is browned and onions are translucent. Drain excess fat.
Stir in marinara sauce, dried oregano, dried basil, salt, and black pepper. Simmer for 5 minutes.
Combine cooked tortellini with the beef and sauce mixture.
Transfer mixture to a shallow white ceramic baking dish.
Sprinkle shredded mozzarella and grated Parmesan evenly over the top.
Bake uncovered for 20-25 minutes or until cheese is melted, bubbly, and golden brown on top.
Let rest for 5 minutes before serving.
Serve a portion on a round white plate, garnished with fresh basil leaves.