Allow one kidney per person (they are big).
Cut the kidney flesh away from the white fatty core (very tough to eat) and soak the pieces in cold water for a while.
For two prepared kidneys:
One medium onion, chopped
Two rashers of streaky bacon, preferably smoked, chopped
One heaped tablespoon tomato puree
A good splash of Worcestershire sauce (to suit)
A splash of Tabasco (or a finely chopped chili, or chili sauce or whatever to introduce heat)
Teaspoon of smoked paprika
250ml or thereabouts beef stock from a cube (Oxo)
Fry the bacon and onion in a little fat until soft. Add the kidney pieces, lightly fry. Add the stock, tomato puree and paprika, stir and cook gently until slightly thickened (the tom puree will act as thickener).
Add Worcestershire sauce, the chili (whichever you decide on using but it is important to add some), seasoning.
Nice served with rice and frozen peas.