01 - In a large bowl, combine ground beef, Italian seasoning, garlic powder, salt, and black pepper. Mix gently until just combined, then shape into 4 equal-sized patties.
02 - Heat olive oil in a skillet or grill pan over medium-high heat. Cook patties for 4 to 5 minutes per side, or until fully cooked through and juices run clear.
03 - Preheat the oven broiler to high. Place the bottom halves of the burger buns on a baking sheet, cut side up.
04 - Spread 1 tablespoon of pizza sauce onto each bun bottom, then place one cooked patty on top of each sauced bun.
05 - Spoon another tablespoon of pizza sauce over each patty. Layer shredded mozzarella cheese, pepperoni slices, thinly sliced red onion, and bell pepper on top.
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. Top with the remaining bun halves and serve hot with extra pizza sauce for dipping.