The problem with Welsh rarebit recipes is that the mixture, containing beer, is quite liquid. You spread it on the toast, only to find that it oozes like lava over the sides once under the grill.
Anne O'Connell's Early Vegetarian Recipes, just out from Prospect Books, may have the answer. You warm your cheese mixture in a pan, and simply pour it over the toast. The recipe, from Mrs C S Peel's Dishes Made without Meat (Constable, 1907), states: "Slice down some good, rich cheese rather thinly, into a delicately clean stewpan, with some morsels of butter, and 2 or 3 spoonfuls of porter, good ale, or new milk as you please, according to the quantity of the cheese [early recipe books tended to assume that their readers could judge quantities]; flavour to taste with freshly ground black pepper and English mustard. Stir it all till thoroughly melted, (and) pour it over hot buttered toast."
But how do you get a browned topping? "With a hot shovel," is Mrs Peel's recommendation.