Veal Kidney in Gin-Mustard Cream Sauce

My husband is the serious kidney lover in our family. I think he’d be happy to eat kidney three times a week. He loves to order it in Paris, and William, the owner of our neighborhood restaurant, always tries to have veal kidney on the menu when we are in town. A former butcher, William is very particular about the kidneys he buys and so should you be. At William’s, kidney is always prepared the same way: whole in a mustard cream sauce and rose—or pink—in the center. This is my husba