These Hungarian Potato Dumplings (Shlishkes) are made with mashed potatoes and covered with buttered bread crumbs. A perfect side dish!
3 lb (1350g) potatoes , unpeeled, scrubbed
1 egg , lightly beaten
yolk of 1 egg , lightly beaten
2 1/2 cups all-purpose flour , plus more as needed
1 stick (115g) butter
1 cup fine bread crumbs