Take 1 fresh veal kidney, slice the outer red part of the kidney into 1cm thick pieces. Be sure to cut around the core of the kidney, which is a white tissue mass that's too tough to eat. Discard the core.
Soak the kidney slices in a bowl of cold water for 10 mins to wash off the blood. Meanwhile, finely chop 1 shallot, and mince 1 tbsp of fresh parsley.
Remove kidney slices from the water, and pad dry with a paper towel. Dust each slice of kidney on both side with flour.
Heat the butter in a heavy bottom frying pan, brown the kidney slices on medium heat, for about 1 to 2 minutes on each side.
Add chopped shallot, hot water, vinegar, mushroom ketckup, minced parsley, salt and pepper to taste. Simmer on medium heat for 5 minutes uncovered, while the liquid is reduced to a gravy.
Mushroom ketchup is a traditional condiment originated from the United Kingdom. I make my own mushroom ketchup using this recipe. You can also buy mushroom ketchup ready-made.
Veal kidney is tender and doesn't take much time to cook. In fact, over-cooking veal kidney will make it tougher to eat. If using other kidney as replacement, such as beef kidney, you will need to increase the cooking time to stew the kidney until tender.
This recipe is adapted from the "Scots Kidney Collops" recipe in The Scots Kitchen cookbook. The original recipe is a few hundreds years old, which also suggests that "some good cooks season this dish with an anchovy and lemon-pickle; others add made mustard". Give them a try, and have fun in the kitchen!
~ Nourishing Recipes Based on Ancestral Wisdom & Modern Science ~