Preheat the oven to 375°F.
Cut off the tops of the bell peppers and remove the seeds and membranes. Set aside.
In a large skillet, cook the ground beef and onion over medium heat until the beef is browned and the onion is soft.
Drain any excess fat from the skillet.
Add the cooked rice, tomato sauce, garlic powder, onion powder, salt, black pepper, paprika, and cayenne pepper to the skillet. Stir well.
Fill each bell pepper with the beef and rice mixture.
Place the stuffed peppers in a baking dish and cover with foil.
Bake in the preheated oven for 35 minutes.
Remove the foil and sprinkle the shredded cheddar cheese over the top of each pepper.
Bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Serve hot and enjoy!