Rognons À La Moutarde

• 2 veal kidneys, cleaned, dried on paper towel and cut into 1.5in cubes (if you have trouble finding these, you can also try lamb's kidneys, about 12)
• 2 shallots, finely minced
• 1 cup dry white wine
• 9 ounces button mushrooms, cleaned and sliced
• 8 tablespoons butter
• 1 tablespoon olive oil
• 1/2 cup creme fraiche
• 1 cup veal stock (if you don't have any in your freezer, use good quality bought)
• 2 tablespoons whole grain mustard
• salt and pepper to taste

1. Note: A few principles to remember when working with kidneys. First you must emove the membrane, then cut kidneys in two lengthways. Cut out the central fat inside (the white stuff, looks like branches). Secondly, please please please do not overcook the kidney or you'll be chewing rubber. And finally, once you have added mustard to the sauce, don't let it come to the boil again.
2. In a pan, melt 3 tablespoons butter and saute the mushrooms, season and set aside.
3. Heat another pan and add 5 tablespoons butter and oil. Once very hot, almost smoking, add the kidneys (BE CAREFUL, oil could splatter). Saute kidneys for 1-2 minutes until they are nicely browned, then remove them from the pan and drain them in a sieve over a bowl.
4. Add the shallots to the fat in the pan, letting them sweat over low heat for 2 minutes. Tip in the wine and turn up the heat, cooking for another 5 minutes to reduce.
5. Pour in the creme fraiche and let it reduce by half. Then add the veal stock, taste for seasoning and take off the heat. Add the mustard whilst stirring the sauce, put back on the heat and add the kidneys and the mushrooms. Heat through for about 5 minutes (without letting it come to a boil). Do one last taste for seasoning and serve.
6. You could just serve this over rice, but for a really decadent dinner, try it over fresh tagliatelle tossed in butter and grated parmesan, lip-smackingly good!

veal kidneys, shallots, white wine, button mushrooms, butter, olive oil, crueme fraueeche, veal stock, whole grain mustard, salt

Taken from food52.com/recipes/2778-rognons-a-la-moutarde (may not work)