1 (16 ounce) can refrigerated biscuits
9 ounces frozen, fully-cooked bite-size meatballs, thawed and quartered (I used 18 small meatballs)
1/2 cup frozen diced onion (or about half of small fresh onion, finely diced)
2 sweet bell peppers (any color is fine, but I used 1 red and 1 green), finely diced
2 cups (8 ounces) shredded cheddar cheese, divided