Beef Kidney with Mustard.
(Rognon de Bœuf au Moutard.)
Take an ox kidney, remove the core, cut it up in slices about a quarter of an inch thick, and season it with pepper and salt; put two ounces of butter or beef dripping into a pan with four finely minced onions; fry these for ten to fifteen minutes, then add the kidney, cover the pan down, and let these cook together for twelve to fifteen minutes; strain off the fat, then add half a pint of good thick tomato sauce and a dessertspoonful of French vinegar; boil up together and add a teaspoonful of chopped fresh parsley, and a teaspoonful each of French and English mustard mixed; then dish on a hot dish with a purée of spinach or endive round as a border. Serve for an entrée for luncheon or dinner.