In a large mixing bowl, combine 2 cups flour, sugar, yeast and salt. In a saucepan, heat milk, shortening and water to 120 degrees F-130 degrees F. Add to dry ingredients; beat until moistened. Add mashed potatoes and eggs; beat until smooth. Stir in enough remaining flour to form a stiff dough. Do not knead. Place in a greased bowl, turning once to grease top. Cover and refrigerate for several hours or overnight.

Turn dough onto a lightly floured surface and punch down. Divide in half. With greased hands, shape each portion into 12 balls. Roll each ball into an 8-in. rope; tie into a knot. Place 2 in. apart on greased baking sheets; tuck ends under. Cover and let rise until doubled, about 2 hours. Bake at 375 degrees F for 25-30 minutes or until golden brown. Remove from pans to wire racks.