Heat the olive oil in a skillet over medium heat, and saute the red onion and bell pepper until softened. Set aside.
Place the ground beef into a mixing bowl with 3 Tbsp of the pizza sauce, the garlic powder, onion powder, Italian seasoning and salt and pepper to taste. Knead the mixture until well combined.
Form the meat into two large patties, and place into a skillet over medium high heat.
Saute the burgers until done to your liking.
Top each burger with two slices of mozzarella cheese.
Place a burger patty onto the bottom of each bun.
Top the burger patties with some of the pizza sauce and slices of pepperoni.
Add some of the onions and peppers to the top of each burger.
Layer some sauce on the underside of the tops of the buns, and place the tops onto the burgers.