In a small bowl, dissolve 2¼ teaspoons of instant dry yeast with 1 cup of warm milk and 1 tablespoon of sugar. Allow to stand for 5 minutes until foamy.

In a large mixing bowl, combine the foamy yeast mixture with ½ cup of sugar, 1 cup of mashed sweet potato puree, ¼ cup of melted butter, 1 teaspoon of salt, and 2 eggs. Mix well until smooth.

Gradually add in 3 to 4 cups of all-purpose flour, mixing until dough is smooth and slightly sticky.

Shape the dough into a ball, coat lightly with oil, and cover with a towel. Let rise in a warm area for about 1 hour until doubled in size.

Punch down the risen dough and let it rest for 2 minutes. Divide into 16 to 20 pieces and shape each into a ball.

Arrange rolls in a greased baking dish, cover, and let rise for another 30-45 minutes until doubled.

Preheat oven to 350°F (175°C). Bake rolls for 15-20 minutes until golden brown.

Brush the tops with cold butter as soon as they are out of the oven. Serve warm.