01 - In a large bowl, combine ground beef, Italian seasoning, garlic powder, salt, and black pepper. Mix gently until just incorporated, then shape into 4 equal-sized patties about 3/4 inch thick.
02 - Heat olive oil in a skillet or grill pan over medium-high heat. Sear the patties for 4 to 5 minutes per side until fully cooked through and juices run clear.
03 - While the patties cook, set the oven broiler to high. Arrange the bottom halves of the burger buns on a baking sheet lined with foil.
04 - Spread 1 tablespoon of pizza sauce evenly 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, pepperoni slices, sliced red onion, and bell pepper strips.
06 - Slide the baking sheet under the broiler for 1 to 2 minutes, watching closely, until the mozzarella is fully melted and bubbling.
07 - Remove from the oven and garnish with fresh basil leaves or a pinch of red chili flakes if desired. Cap each burger with the top bun half and serve immediately with extra pizza sauce for dipping.