Preheat the oven to 350 degrees F.
Cook ground beef until well done. Strain to remove grease. Saute the green pepper, corn, onion, roasted peppers, and steak seasoning in butter until tender. Strain off any excess butter. Mix with the ground beef and add tomatoes. Layer this mixture in bottom of baking dish. Cover with warm mashed potatoes. Top with cheddar cheese. Bake until the cheese melts.