Combine 1/4 cup warm water with 1 tablespoon sugar and 2 packages active dry yeast in a small bowl. Stir and set aside. In a large bowl, mix 1 cup buttermilk with 1 cup mashed potatoes, 1/4 cup melted butter, 1 large egg, 1 tablespoon sugar, and 1 teaspoon salt. Stir well and add the yeast mixture and 1 cup all−purpose flour. Work in another 3 cups flour, 1 cup at a time, until the dough is stiff enough to knead. Knead for 4 to 5 minutes on a lightly floured surface until the dough is smooth and elastic. Turn the dough into a lightly oiled bowl, cover, and let rise for an hour, until the dough doubles in size.
Grease 24 muffin tins. Punch the dough down gently and push out all the air bubbles with your palm. Pinch off small pieces of dough to form 1−inch
balls. Put 3 dough balls in each muffin cup until all the dough is used,
cover, and let rise for 30 to 40 minutes. Bake in a preheated 350 degree F
oven for 10 to 15 minutes, until browned. Brush the rolls with melted butter as soon as you remove them from the oven. Serve warm