5 tablespoons canola oil
2 cups frozen chopped onions
1 1/2 pounds ground beef, 85 percent lean
2 tablespoons grill seasoning
1/4 pound blue cheese, sliced into 4 pieces
2 slices Cheddar, each piece cut into 4 pieces
2 slices mozzarella cheese, each piece cut into 4 pieces
12 small potato dinner rolls, sliced in 1/2 and toasted (recommended: Martin's)
1/4 cup ketchup
1 (12-ounce) jar roasted red peppers
1/2 cup mayonnaise
2 tablespoons pesto