In a large mixing bowl, combine sourdough starter, water, butter, flour, dry milk, potato buds, sugar, yeast and salt. Mix together with dough hook, adding more water if necessary to make a soft, smooth dough. Knead for 4-5 minutes. Place the dough in a lightly greased bowl and cover with plastic wrap. Allow to rise until double, 60-90 minutes.
Grease 2 round cake pans. Transfer the dough to a lightly floured work surface. Gently deflate and divide into 14-16 pieces. Shape each piece into a ball. Place seven to eight balls in each pan. Cover each pan and allow the rolls to rise until puffy, about 60-90 minutes.
Preheat oven to 350 degrees. Bake the rolls for 25-27 minutes until golden brown. Remove from oven and spread melted butter over tops. Transfer to a wire rack to cool. Makes 14-16 rolls.
*Unless otherwise indicated, all butter on this site is salted.*If your sourdough starter is good and "ripened" or bubbly, you may opt not to use yeast. If you want to be certain that your rolls rise within a designated time, then you may want to use the instant yeast. Not using yeast may result in a longer rising time.