Cook rice according to package instructions, about 15-20 minutes. Set aside to cool.

Preheat your oven to 400°F (200°C).

Cut off the tops of the bell peppers and remove seeds and membranes.

In a large skillet, heat olive oil. Sauté chopped onion until translucent. Add ground meat and cook until browned, about 6-8 minutes. Stir in minced garlic and cook for an additional 30 seconds.

Add diced tomatoes and tomato sauce to the skillet. Mix in Italian seasoning, salt, pepper, and garlic powder. Simmer for 5 minutes. Fold in the cooled rice and half of the cheese.

Stuff each bell pepper with the meat and rice mixture. Place upright in a baking dish and pour ½ cup of water in the bottom.

Top with remaining cheese.

Cover the dish with aluminum foil and bake for 30 minutes. Remove foil and bake for another 5 minutes until cheese is melted and bubbly.