Various recipes for Welsh rarebit include the addition of ale, mustard, ground cayenne pepper or ground paprika and Worcestershire sauce. The sauce may also be made by blending cheese and mustard into a sauce béchamel (a sauce Mornay). Some recipes for Welsh rabbit have become textbook savoury dishes listed by culinary authorities including Escoffier, Saulnier, Hering and others, who tend to use the form Welsh rarebit, emphasizing that it is not a meat dish. In the United States, a frozen prepared sauce by Stouffer's can be found in supermarkets.
Acknowledging that there is more than one way to make a rarebit, some cookbooks have included two recipes: the Boston Cooking-School Cook Book of 1896 has two recipes, one béchamel-based, the other with beer, The Constance Spry Cookery Book of 1956 has two recipes, one with flour and one without, Le Guide Culinaire of 1907 has two recipes for 'Welsh Rarebit', one with ale and one without.
The term rarebit is to some extent used for variants on the dish, especially buck rarebit which has a poached egg added, either on top of or beneath the cheese sauce.
It is also possible that the dish was attributed to Wales because the Welsh were considered particularly fond of cheese, as evidenced by Andrew Boorde in his Fyrst Boke of the Introduction of Knowledge (1542), when he wrote "I am a Welshman, I do love cause boby, good roasted cheese. In Boorde's account, "cause boby" is the Welsh caws pobi, meaning "roasted cheese". It is the earliest known reference to cheese being eaten cooked in the British Isles but whether it implies a recipe like Welsh rabbit is a matter of speculation.
A legend mentioned in Betty Crocker's Cookbook claims that Welsh peasants were not allowed to eat rabbits caught in hunts on the estates of the nobility, so they used melted cheese as a substitute. The cookbook writes that Ben Jonson and Charles Dickens ate Welsh rabbit at Ye Olde Cheshire Cheese, a pub in London. There is no good evidence for any of this; what is more, Ben Jonson died almost a century before the term Welsh Rabbit is first attested.
The term Welsh rarebit was evidently a later corruption of Welsh rabbit, being first recorded in 1785 by Francis Grose, according to the Oxford English Dictionary. The entry in Merriam-Webster's Dictionary of English Usage is "Welsh rabbit, Welsh rarebit" and states: "When Francis Grose defined Welsh rabbit in A Classical Dictionary of the Vulgar Tongue in 1785, he mistakenly indicated that rabbit was a corruption of rarebit. It is not certain that this erroneous idea originated with Grose....
According to the American satirist Ambrose Bierce, the continued use of rarebit was an attempt to rationalize the absence of rabbit, writing in his 1911 Devil's Dictionary: "RAREBIT n. A Welsh rabbit, in the speech of the humorless, who point out that it is not a rabbit. To whom it may be solemnly explained that the comestible known as toad in the hole is really not a toad, and that ris de veau à la financière is not the smile of a calf prepared after the recipe of a she banker.
In his 1926 edition of the Dictionary of Modern English Usage, the grammarian H. W. Fowler states a forthright view: "Welsh Rabbit is amusing and right. Welsh Rarebit is stupid and wrong.
The word rarebit has no other use than in Welsh rabbit and "rarebit" alone has come to be used in place of the original name.