Lambs' Kidneys with Two Mustards

First prepare the kidneys: cut them in half horizontally and snip out the white cores with scissors – if you don't the kidneys will be tough – then peel off and discard the skins.

Next place the frying pan over a high heat and heat the butter and oil together. When it's hot and foaming, add the kidneys and cook for 3 minutes, turning them over halfway through. Next remove them to a plate, then add the onion to the pan and, keeping the heat high, cook for 3-4 minutes, until softened and brown at the edges. Now add the mushrooms and cook for another 1-2 minutes, until the juices just start to run out, then add the white wine and let it bubble and reduce to half its original volume.

Finally, add the crème fraîche and mustards. Now give everything a good seasoning, stir well and carry on reducing the liquid for 2-3 minutes. Finally, return the kidneys and their juices to the sauce and heat through for about 1 minute.

Serve right away with plain basmati rice.