01 - In a large bowl, combine the ground beef, Italian seasoning, garlic powder, salt, and black pepper. Mix gently until evenly incorporated, then shape the mixture into 4 equal-sized patties.
02 - Heat olive oil in a skillet or grill pan over medium-high heat. Sear the patties for 4 to 5 minutes per side, or until cooked through and no longer pink in the center.
03 - Preheat the oven broiler to high. Place the burger bun bottoms cut-side up on a baking sheet.
04 - Spread 1 tablespoon of pizza sauce onto each bun bottom. Place one cooked patty on top of each sauced bun.
05 - Spoon another tablespoon of pizza sauce over each patty. Layer on the shredded mozzarella cheese, pepperoni slices, sliced red onion, and sliced bell pepper.
06 - Place the baking sheet under the broiler for 1 to 2 minutes, watching closely, until the cheese is bubbly and fully melted.
07 - Remove from the oven and garnish with fresh basil leaves or red chili flakes if desired. Cap each with the top bun half and serve immediately with extra pizza sauce on the side for dipping.