Dissolve the yeast and 1 tablespoon of sugar in the warm milk in a medium mixing bowl. Let stand for 5 minutes.
To the bowl with the milk, add the rest of the sugar, mashed sweet potato, butter, salt, and eggs. Mix until well combined.
Mix in 3 cups of flour, adding 1/2 cup at a time and mixing until just combined. Once the flour is mixed in, continue mixing in up to another 1/2 cup (1 tablespoon at a time) as needed. The dough shouldn't be sticking to the bowl.
Shape the dough into a ball and place it in a large mixing bowl. Cover the bowl with plastic wrap. Let rest on the counter for about 1 hour or until doubled in size.
Punch down the dough and divide it into 10 equal portions (just eyeball this). Roll each portion into a ball and place them in a greased 9-inch x 13-inch baking dish.
Cover the baking dish with plastic wrap again. Allow the dough to rise again until doubled, about 1 hour.
Preheat the oven to 350 degrees F. Bake the rolls for 15 to 20 minutes or until the tops are golden.
In a small bowl, stir together the sugar and cinnamon for the topping until evenly combined.
Remove the rolls from the oven and brush the tops with butter. Sprinkle the cinnamon-sugar all over the rolls before servings warm.
Notes
The yield and nutrition for this recipe may vary depending on the size of the dough balls. You can make a large number of smaller rolls if desired.