Kopytka with Mushroom-Mustard Sauce

Kopytka literally means “little hooves,” because, apparently, they look like them. I think these simple potato dumplings actually look more like diamonds. Kopytka are Polish gnocchi, and they’re a little more rustic than the Italian version. The secret to good kopytka is to boil potatoes in their skins, so they won’t absorb too much water and you can add less flour for softer, lighter dumplings. Feel free to add more or less flour to get the dough to feel soft and not t