In a large bowl, sprinkle the yeast over water; stir to dissolve. Add sugar, salt, eggs and milk. Blend in a mixer. Add 4 cups of the flour. Beat until smooth. Add shortening; beat in the remaining flour. Cover and chill for several hours; overnight is better. Roll out on a floured board to 1\/8 inch thickness Cut into 2.5 inch squares. Deep fry at 360 turning until both sides are golden brown. Sprinkle with powdered sugar. Serve immediately.