This makes a good breakfast or brunch dish, or you can serve it as a light main course. Always try to buy fresh lambs’ kidneys, as they will have a better texture when cooked than frozen ones.
Heat a frying pan until almost smoking. Season the kidneys with salt and cayenne pepper and fry them in a little oil for 2 minutes over a high heat until coloured but still pink. Transfer them to a plate.
Melt the butter in a saucepan, add the shallots and garlic, and cook gently for a couple of minutes until soft. Add the cider vinegar, mustard and ketchup, an