In a bowl, mix ground beef with Italian seasoning. Form into 4 equal-sized patties and sprinkle with salt and pepper.
Preheat the grill to medium-high heat. Grill patties for about 4 minutes on each side or until they reach an internal temperature of 160°F.
Toast the hamburger buns lightly. Place a patty on each bun, top with a tablespoon of marinara sauce, a slice of mozzarella cheese, and 2-3 slices of deli pepperoni.
Return to the grill or place under a broiler just until the cheese melts and then serve.