Dissolve yeast in warm water, let it sit for 5 minutes.
Mix mashed sweet potatoes, warm milk, melted butter, sugar, and salt in a large bowl.
Add yeast mixture to the bowl and stir well.
Gradually add flour, mixing until a soft dough forms.
Knead the dough on a floured surface for about 10 minutes.
Place dough in a greased bowl, cover, and let it rise for 1 hour.
Punch down the dough and shape it into rolls.
Place rolls on a greased baking sheet, cover, and let rise for another 30 minutes.
Preheat oven to 375°F (190°C).
Bake rolls for 20-25 minutes or until golden brown.