Preheat oven to 400 degrees. Cut off the top of 5 bell peppers about 1-inch down from the top. Clean out seeds and membranes. Throw away tops. Set of bell peppers aside.

In a large, nonstick pan, cook ground beef and onions over medium-high heat, stirring frequently, until beef is no longer pink; drain. Stir in taco seasoning mix, water, black beans, tomato sauce, and corn. Bring to a boil, reduce heat to medium-low; simmer 5 minutes. Stir occasionally.

In an un-greased baking dish, arrange peppers. Spoon Mexican mixture evenly into each, about 1 cup filling for each. Pour 1 cup of water in the bottom of the baking dish. Cover the dish with foil.

Bake 45 minutes, until the peppers are tender. It might need 5 additional minutes for the peppers to be soft.

Top each serving with lettuce, fat-free sour cream or plain yogurt, and salsa, if desired.

These freeze great. Wrap each individually in plastic wrap and place in a Ziplock freezer bag.