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