Mix together well the sugar, potatoes, shortening, eggs and salt.
Dissolve the yeast in the water; then add that to the above mixture.
Stir in about 3 cups flour. Add the remaining flour until the dough is still somewhat sticky. Let rise until doubled.
Pour out on floured board, roll out to around 3/4″ thick, cut with a 2″ cookie cutter, place on greased cookie sheet.
Brush with milk just before baking. Bake until golden brown, about 10-15 minutes. 375 degree oven.