Heat broiler to high. Move oven rack to top section. Broil red bell pepper about 1-2 minutes in each side, until roasted. Remove from oven and let pepper steam in a brown paper lunch bag for five minutes. Carefully remove loose skin and slice into rings. Set aside.
Heat oven to 375. Brow ground beef and onions together until onions are tender and beef is no longer pink. Season with salt and pepper to taste.
Stir in corn and undrained tomatoes until throughly mixed. Heat through on medium high, about five minutes.
Stir in flour and butter and bring to a boil. Lower heat, and let simmer about fifteen minutes. Mixture should thicken.
Pour into 8in square casserole dish. Top with red pepper rings.
Bake, uncovered, for 30 mins. Let cool a bit before serving, as mixture will be very hot.