Sweet Potato Crescent Rolls

In a large mixing bowl, dissolve yeast in warm water. Let stand for 5 minutes. Beat in the sweet potatoes, sugar, egg and salt. Combine cold butter with 3 cups of flour, using a pastry cutter or two knives, until the butter chunks resemble coarse crumbs. Combine with wet ingredients. Add enough of the remaining flour to form a stiff dough. Turn onto a floured surface and knead until smooth and elastic, about 6-8 minutes. Place it in a greased bowl, turning once to grease the top. Cover and let rise in a warm place until doubled, about 1 hour. Rising time may be less if you use instant yeast, which I always do. Punch dough down; divide into thirds. Roll each portion into a 12 inch circle; cut each into 12 wedges. Brush with the melted butter. Roll up from the wide end of the triangle and place, pointed end down, 2 inches apart on greased baking sheets. Cover and let rise until doubled, about 40 minutes. Bake at 375 degrees for 13-15 minutes or until golden brown. Remove from pans to wire racks. Serve warm.