Ingredients:

1-1/2 lb ground beef,
4 slices sweet onion,
vegetable oil,
8 slices Swiss cheese,
4 crusty rolls, split and toasted.
4 romaine lettuce leaves,
4 slices tomato.

Sauce:
1/4 C mayonnaise,
1 T Dijon-style mustard.
Combine sauce ingredients,set aside.

Directions:

Shape ground beef into four patties using BurgerMate.Lightly brush onion with oil. Place patties and onion on grill over medium,ash-covered coals.Grill, uncovered, 13 to 15 minutes or until centers of patties are no longer pink and onions are tender, turning occasionally (you could also broil or pan broil the burgers). Season burgers with salt and pepper if desired, after turning. Approximately 1 minute before burgers are done,top each with 2 cheese slices. Meanwhile spread sauce on top half of each roll. Line bottoms of rolls with lettuce and tomato; top with cheeseburger and onion.Close sandwiches and serve.