Rognons à la Moutarde

Skin the kidneys if necessary, halve them and cut out the core with scissors; cut veal kidneys in chunks or lamb’s kidneys in half to form crescents. Heat the butter in a frying pan and add the kidneys with salt and pepper. Sauté over a very high fire for 2—3 minutes for veal or 1-2 minutes for lamb’s kidneys, or until brown on all sides but still pink inside. Don’t overcook or they will become