In a medium skillet, melt butter over medium heat. Add onion and sugar. Cook, stirring frequently, about 20 minutes or until onion turns golden. Remove skillet from heat. Season to taste with salt and black pepper.
Meanwhile, on a clean work surface, roll or pat each biscuit to a 6-inch-diameter circle. Build up edges slightly. Place on an extra-large ungreased baking sheet.
Divide onion among biscuits. Sprinkle with bacon. Top each with about 2 tablespoons of the sweet pepper. Sprinkle with Parmesan cheese.
Bake in a 450 degree F oven about 12 minutes or until the biscuits are done. Cut each of the wheels into 4 wedges. Serve warm. Makes 10 servings.