Mix 2 cups mashed potatoes with 1 egg yolk and 1 tablespoon grated onion. Shape rolls about 2 1/2 inches long and thick as a finger. Coat with flour then roll in egg plus 2 tablespoons water; then in fine bread crumbs. Melt 4 to 5 tablespoons Crisco in skillet and slowly fry potato logs turning to brown all over.