Cut tops off peppers. Remove and discard stems. Finely chop tops; set aside. Scoop out seeds and membrane. Place peppers cut side up in baking dish just large enough to hold them upright.

In large skillet over medium-high heat, heat oil. Add onions and chopped peppers. Cook 3 to 4 minutes or until softened. Add garlic, chili powder, cumin, red pepper flakes, salt and pepper. Cook 1 minute. Add tomato sauce. Cook until heated through. Stir in chopped meatloaf, rice and 1 cup cheese.

Fill peppers with rice mixture. Pour small amount of water in bottom of baking dish. Cover with foil. Bake 30 minutes. Uncover. Top with remaining cheese. Bake 5 to 10 minutes or until the peppers are soft and cheese is melted.