Heat oil in deep-fryer to 375 degrees F (190 degrees C).
In a large bowl, beat together white sugar, butter, eggs and applesauce. In a separate bowl, stir together flour baking powder, salt, baking soda, mace and cinnamon. Stir flour mixture into the egg mixture alternately with the buttermilk. Mix until a stiff dough is formed.
Turn dough out onto a lightly floured surface. Roll into a 3/4 to 1 inch thick sheet. Make sure to roll the dough to an even thickness. Cut out doughnuts with a doughnut cutter.
Carefully slide doughnuts into hot oil. Turn doughnuts as soon as they rise to the surface. Fry until golden brown on both sides. Drain on paper towels and dust with confectioners' sugar. Serve hot.