01 - In a large bowl, combine the ground beef, Italian seasoning, garlic powder, salt, and black pepper. Mix 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 fully cooked through and juices run clear.
03 - While the patties cook, preheat the oven broiler to high. Arrange the bottom halves of the burger buns on a baking sheet.
04 - Spread approximately 1 tbsp of pizza sauce onto each bun bottom. Place one cooked patty on top of each sauced bun.
05 - Spoon another tbsp of pizza sauce over each patty. Layer with shredded mozzarella, pepperoni slices, thinly sliced red onion, and bell pepper strips.
06 - Transfer the baking sheet under the broiler for 1 to 2 minutes, watching closely, until the mozzarella is bubbly and fully melted.
07 - Remove from the oven. Garnish with fresh basil leaves or red chili flakes if desired, then cap each with the top bun half. Serve immediately with extra pizza sauce on the side for dipping.