Sweet Potato Rolls
["1 large yam", "1 pkg. active dry yeast or 1 cake compressed", "1 tsp. salt", "3 Tbsp. sugar", "1 Tbsp. butter", "1 c. milk", "3 1/2 to 4 1/2 c. sifted all-purpose flour"]
["Pare yam and cut in several pieces.", "Add enough water to cover and cook until tender.", "Drain, saving 1/4 cup of water in which yam was cooked.", "Cool yam-water to lukewarm and dissolve the yeast in it.", "Mash yam; then beat in salt, sugar and butter vigorously. Heat milk until a film shines on top; skim.", "Stir into yam mixture and cool to lukewarm.", "When right temperature has been reached, add the softened yeast.", "Stir in flour, a cupful at a time, until dough is thick enough to knead.", "Lift onto a floured board and knead until smooth and elastic.", "Place in a greased bowl.", "Cover with a tea towel and let rise in a warm place until double in size.", "Bake in preheated oven at 425\u00b0 for 13 to 15 minutes."]
["yam", "active dry yeast", "salt", "sugar", "butter", "milk", "flour"]