Preheat broiler or grill to medium heat. Combine ground sirloin and Mrs. Dash® Original Steak Blend. Divide into 8 portions. Shape each into a patty about 4 inches (10cm) in diameter and 1/4 inch (.6 cm) thick. Combine remaining ingredients. Divide cheese and veggies mixture between 4 of the patties, spreading to within 1/2 inch (1.25cm) of edges. Cover with second patty, sealing edges well. Cook 4 to 5 minutes per side or until meat reaches 160°F (71°C) and is no longer pink. Serve on toasted buns topped with additional cheese, if desired.