Zesty Barbecue Cheeseburgers

Ingredients

• 1 pound Ground Beef (93% lean or leaner)
• 1/4 cup finely chopped red onion
• 4 tablespoons barbecue sauce, divided
• 4 slices white Cheddar, pepper Jack, smoked Gouda or provolone cheese
• 4 whole wheat hamburger buns or pretzel rolls, split, toasted
• Lettuce leaves, tomato slices and red onion slices (optional)