Spread a thin layer of butter or margarine on the outside of the toast slices. Place a slice of cheese on each toast, then a layer of thinly sliced onion, sprinkle well with cayenne pepper or chilli, 1 slice of ham (possibly also 2 slices) and another slice of cheese on top and top with a toast slice.
With the greased bread sides facing outwards, toast quickly until crispy brown in the contact grill and serve with mayonnaise and / or ketchup.