Cook ¾ cup of uncooked brown rice according to package instructions.

Preheat your oven to 400°F (200°C).

Prepare your 6 bell peppers by cutting off the tops and removing the seeds.

In a skillet, heat 2 teaspoons of olive oil over medium heat and sauté ¾ cup of chopped yellow onion for 2-3 minutes.

Add 1 pound of ground beef, crumbling it and cook until no longer pink, about 5-7 minutes.

Add 3 cloves of minced garlic and cook for 30 seconds. Stir in 15-ounce can of diced tomatoes, 8 ounces of tomato sauce, and 2 teaspoons of Italian seasoning. Simmer for 5 minutes.

Remove skillet from heat and fold in the cooked rice and half of 1 cup of shredded mozzarella cheese until well combined.

Spoon the filling into the hollowed bell peppers and sprinkle remaining mozzarella cheese on top.

Cover with aluminum foil and bake for 30 minutes, then uncover and bake for an additional 5 minutes.

Remove from the oven, let cool for a few minutes, and serve warm.