In a large saucepan, sauté ground beef, onion, pepper, and garlic until beef is fully browned. Drain fat.
Stir chili ingredients into saucepan: diced tomatoes, tomato sauce, vinegar, 1 ½ T. brown sugar, 1 ½ T. chili powder, cumin, 1 tsp. Worcestershire sauce, cayenne, and red pepper flakes. Bring sauce to a simmer over medium heat. Let simmer 10-15 minutes or until thickened. Stir in beans and set aside.
While sauce is simmering, preheat oven to 350 degrees. Lightly spray a 13×9 baking dish with cooking spray.
Slice both sheets of Party Rolls in half horizontally, keeping the rolls connected. Lay the bottom sheets of rolls side-by-side in the baking dish and bake for about 5 minutes, or until toasted, to dry out the rolls so they will not get soggy when the chili mixture is added.
When rolls are toasted, remove from oven and top with the chili joe mixture and cheddar cheese. Place the tops of the rolls on top of mixture.
Combine together remaining ingredients: butter, 1 T. brown sugar, 1 tsp. Worcestershire sauce, onion flakes, poppy seeds, 1 tsp. chili powder, and hot sauce. Gently spoon mixture over the rolls.
Bake in oven for 15-20 minutes or until cheese melts and chili joe filling is heated through. Serve warm.