Over medium heat, saute beef, onions, and red pepper until browned.
Stir in Mezzetta Pepperoncini Peppers and barbecue sauce. Remove from heat.
Spray 9 X 9 glass baking dish with cooking spray. Slice party rolls in half and lay bottom of rolls in the bottom of your glass baking sheet. Spread the bottom roll layer with the beef mixture. Top with sliced American cheese and then place the top of buns over the cheese layer.
Microwave butter, brown sugar, and Worcestershire sauce for 60 seconds (in 30-second intervals)
Brush tops of buns with the mixture and sprinkle with toasted sesame seeds.