In a large bowl, stir together the yeast, water, and granulated sugar. Let stand 5 minutes.
Add in the brown sugar, mashed sweet potato, butter, salt, and eggs. Use a whisk or electric hand mixer to combine. Add 3 cups of the flour and mix until it comes together as a dough.
Sprinkle the remaining 1/2 cup of flour onto a large cutting board or countertop. Knead the dough for about 5 minutes or until you have a soft slightly tacky dough.
Oil a large mixing bowl, and place the kneaded dough in the bowl. Flip and turn the dough a few times to coat all the sides with oil.
Cover with a kitchen towel and let the dough rest about an hour (or until doubled in size). Punch the dough down and divide into 16 pieces.
Roll each section into balls and place in a greased 13x9" baking dish.
Cover and let rise again for about 30 minutes. Bake at 375 degrees for about 20 minutes or until roll tops are golden brown.