Makes 4 dozen meduim-sized rolls
Mix scalded milk, potato water and mashed potatoes. Cool.
Add crumbled yeast. (If you're using dry yeast, dissolve in ¼ cup of the warm potato water first.)
Cream butter with sugar and add the salt and the eggs. Add to first mixture alternately with the flour to make a stiff dough, using additional flour if necessary.
Knead the dough 1 minute. Let rise overnight in a warm place.
In the morning roll out 1 inch thick, using more flour on the board if necessary to make the dough of good consistency. Sprinkle generously with brown sugar and cinnamon. Roll as for jelly roll. Cut into 1-inch pieces and place, edges just touching, on a greased baking pan at least 2 inches deep. Let rise until doubled in size.
Bake in a preheated 350° oven about ½ hour. Glaze with a thin water and powdered sugar frosting.