On a medium or high heat sauté the onion and red pepper in a skillet or a frying pan (if on high heat, make sure to stir frequently). Spread refried black beans on a corn tortilla; cover it with sautéed onion and red peppers. Add shredded sharp cheddar cheese (older the better) and cover it with another tortilla. Place it in a pan on medium heat (one can add oil to the pan, I prefer to butter up the tortillas once cooked) and cook until both sides are golden brown and cheese has melted. Enjoy!