Sweet Potato Yeast Rolls

1 package (1/4 ounce) active yeast (2 3/4 teaspoon)
1 cup warm milk (110*F-115*F)
1 tsp plus 1/3 cup white sugar, divided
1/3 cup cold mashed sweet potatoes (canned or fresh)
2 eggs separated
2 Tbsp butter, softened
3/4 tsp salt
3 1/2 to 4 cups flour
4 tsp cold water
1 Tbsp sesame seeds (optional)

In a large mixing bowl, dissolve yeast in warm milk. Add 1 tsp sugar; let stand for 5 minutes. Add the sweet potatoes, egg yolks, butter, salt, remaining sugar, and 2 cups of the flour. Beat until smooth. Mix in enough of the remaining flour to form a soft dough. Turn out onto a floured surface and knead until smooth and elastic (or knead in the mixer for 6-8 minutes). Place in a oiled bowl, turn once to coat. Cover with a damp towel and let rise in a warm place until doubled (1 1/2 hours). Turn dough out onto floured surface; divide into 30 balls. Roll each ball into a 10 inch rope; tie each with a loose knot. Place2 inches apart on baking sheets coated with nonstick cooking spray. Cover and let rise until double (30 minutes). In a small bowl beat the egg whites and cold water; brush over rolls. Sprinkle with sesame seeds. Bake at 350*F for 15-17 minutes or until lightly browned. Remove from pans to cooling rack. Yield: 2 1/2 dozen
Source: Light & Tasty