The Book of Household Management by Mrs. Beeton

634. Cut the kidney into thin slices, flour them, and fry of a nice

brown. When done, make a gravy in the pan by pouring away the fat, putting in a small piece of butter, 1/4 pint of boiling water, pepper and salt, and a tablespoonful of mushroom ketchup. Let the gravy just boil up, pour over the kidney, and serve. BOILED MARROW-BONES.