In large bowl, dissolve yeast in warm water. (If you've just cooked the potatoes, use 1 1/2 cups of warm potato water.) Stir in potatoes, sugar, butter, salt, eggs and 3 cups of the flour. Beat with electric mixer on low speed until smooth. Beat on medium speed 1 minute, scraping bowl frequently. Stir in enough remaining flour to make dough easy to handle.