via Delish
Preheat oven to 400F/205C.
Prepare rice according to directions.
In a large skillet over medium heat, heat oil. Add onion, cook until soft (5min). Stir in tomato paste and garlic, cook until fragrant (1min). Add ground beef and cook until no longer pink (6min). Drain fat.
In the skillet, mix beef, cooked rice, and tomatoes. Add oregano, salt, pepper, simmer about 5 minutes to reduce liquid.
Cut tops off peppers, remove core. (Optional: cut into halves.) Spoon beef mixture into each, top with Monerey Jack. Add to a baking dish.
Cover dish with foil, bake until peppers are tender (35 minutes), uncover and bake until cheese is bubbly (10 minutes more).