Peel 2 medium sweet potatoes and cut them into cubes.
Bring a pot of salted water to a boil over high heat. Add the sweet potato cubes to the boiling water and reduce the heat to low. Cover the pan and cook for about 20 minutes, or until tender.
Drain well and mash. Cool completely and measure 1cup for the recipe.
Add all ingredients to the bread machine in the order suggested by the manufacturer.
Use the basic dough cycle. When the cycle finishes, tear pieces off of the dough to make balls, and place in a greased 9-inch square baking pan so they're just touching but not too close.
Cover the rolls with a cloth and let rise for about 45 minutes in a warm, draft-free place.
Meanwhile, preheat oven to 375 F.
Bake in the oven for about 20 to 23 minutes, until nicely browned.
Brush the tops with melted or softened butter while they're hot.