To call this creamy, savory sandwich melted cheese on toast would be a sacrilege. Welsh rarebit is a traditional snack, ideally based on locally produced Cheddar or Caerphilly cheese, melted and mixed with butter and cream or ale, then poured over a piping hot, buttered toast.
The dish stems from the 14th century as a way of accentuating the greatness of wheat bread and Welsh Cheddar. The debate about rabbit versus rarebit went on until the late 19th century, when the word rarebit caught on. The rabbit version derives from the fact that the Welsh were extremely bad hunters, so their dinners resulted in cheese instead of rabbits.