Turkey Shepherd's Pie with Two Potato Topping

Wondering how to use up those Thanksgiving leftovers? Try this clever turkey shepherd's pie, which uses leftover turkey and gravy for the filling and is topped with a potato–sweet potato mash. The recipe comes from chef Jimmy Bradley of the iconic, now-shuttered Red Cat restaurant in New York City. Leftover turkey sandwich, who? We're making turkey shepherd's pie this year.