"Cooked kidneys should always be tender and slightly pink near the center. The bursting-out of juices is always a problem when they are sautéed in slices. Unless your source of heat is a very strong one, within a few seconds after the slices hit the pan their juices pour out and the kidneys boil and toughen rather than saute. An excellent solution - and in fat, the best method for kidneys in our experience - is to cook the whole kidney in butter, then slice it, and warm the slices briefly in a sauce. However, if you prefer to saute raw sliced kidneys, do so in a very hot butter and oil for only 2 to 3 minutes. They do not brown, they just cook through, turning a uniform gray outside but remaining somewhat pink inside. Then remove the kidneys to a hot dish, make one of the sauces described in the following recipes, and return the kidneys to warm in sauce without boiling... Red Burgundy goes especially well with kidneys."
And then let us know how it went for you. I'll stick with Coq au Vin.
