In a large mixing bowl beat sugar and margarine or butter with an electric mixer until light and fluffy. Add eggs, one at a time; beat well after each addition. Add milk (batter may appear slightly curdled). Stir together flour, mace or nutmeg, and salt. Stir into the egg mixture. Chill 1 to 8 hours.
On a well floured surface, gently roll half of the dough into a 12x6-inch rectangle. Cut into 2-inch squares (do not reroll). Repeat with remaining dough. Fry 3 or 4 squares at a time in deep hot fat (365 degrees F) about 1 minute on each side or until golden, turning once with a slotted spoon. Drain on paper towels. Repeat with remaining squares of dough. Gently shake warm crullers in a bag with powdered sugar or sugar; cool. Makes 36 crullers.