Preheat grill and broiler. Combine turkey, Italian seasoning and parmesan in a bowl. Form into 4 patties. Grill patties 4 minutes on each side or until cooked to desired doneness. While burgers are cooking, arrange buns, cut sides up, on a baking sheet. Brush cut sides of all buns with melted butter. Sprinkle with garlic powder. Place under the broiler for 2-3 minutes or until toasted. Watch closely; they will burn fast. Place 1 burger on 1 bottom bun; top with 1/4 c. mozzarella. Repeat with remaining burgers and remaining bottom buns. Return to broiler. Broil 2-3 minutes or until cheese is melted and beginning to brown. Remove from oven. Top each burger with 2 Tbsp. sauce and top bun.