Dissolve yeast, warm water and 1 Tablespoon white sugar in a large bowl. Let stand 5 minutes or until yeast is bubbly and has risen up.
Add the brown sugar,sweet potato, butter, salt and eggs to the bowl. Beat with electric mixer on low till ingredients are well mixed.
With the mixer still on low speed, add 3 cups of flour to the bowl, mix until flour is just incorporated . Turn the dough out onto a clean lightly floured surface. Knead the dough and add enough flour ( you have a 1/2 cup remaining flour) to make a soft tacky dough. If you need more flour to achieve a soft , elastic tacky dough use slightly more. Do not over knead the dough.
Place your soft, elastic slightly tacky dough in a large bowl coated with oil, turn the dough in the bowl so all sides are coated with oil. Place in a warm, draft free place to rise, cover the top of the bowl with a clean kitchen towel. Let rise till double in size, about an hour.
Punch the dough dough, let it rest for 2 minutes. Divide the dough into 16 pieces rolled into balls. Place in a greased 13x9 inch baking pan. Place in a warm draft free place to rise covered with a clean kitchen towel. The dough will double in size and come up to the top of the pan but not over the pan.
Bake at 375 degrees for about 20 minutes or until roll tops are golden brown. Remove from the oven, let cool.