Place the beef in a bowl with the Worcestershire sauce, salt and pepper.
Mix together well with your hands then divide into 4 and shape into 4 balls.
Place a frying pan over a medium to high heat and add the sliced onions and oil. Fatten each meat ball into a patty shape and place on top of the onions.
Cook for around 5 to 8 minutes each side.
Add the cheese slices on top of the patties for the last few minutes of cooking. Place a lid on top of the pan to melt the cheese faster.
Grill the inside of your burger buns.
Serve the patties in the buns with mayo, sliced gherkins, tomato slices and lettuce leaves.