Take off a little of the kidney fat, mince it very finely, put it in a frying-pan. Slice the kidney, sprinkle it with the parsley and shallots, add a seasoning of pepper and salt, and fry it until nicely browned.
When it is done enough, dredge over a little flour and pour in the gravy and sherry.
Let it simmer, but not boil any more, or the kidney will harden; serve very hot and garnish with croutons. Where the flavour of the shallot is disliked it may be omitted and a small quantity of savoury herbs substituted for it.