For our rendition of this French bistro classic, we lightened things up by swapping whole-milk yogurt for the usual heavy cream or crème fraîche. And to give the sauce texture and layers of mustardy flavor, we use both whole-grain and Dijon mustard. Serve with egg noodles tossed with butter and herbs or with roasted potatoes. The chicken is browned on the stovetop and finishes in the oven, so you will need an oven-safe 12-inch skillet.