500 grams ground beef
small onion, diced
1 cup Ketchup
1/4 cup Mustard
splash of Worcestershire sauce
Salt and freshly ground black pepper
Start by browning the ground beef in a large pot over medium-high heat. Drain off the fat.
Add in the onions. Stir, and then add the ketchup . Stir it around to combine, and then add mustard, Worcestershire, salt and pepper to taste. Stir to combine, and then cover and simmer over medium-low heat, about 10 minutes.
To serve, spread the rolls with the butter and brown them on a griddle or in a skillet. Spoon a good amount of the meat mixture onto the bottom roll, and then top with the other half. Sprinkle with grated cheese.
Serve with chips, salad or just enjoy it by itself.