Preheat oven to 350 °F. In a large bowl of mixer, cream butter with sugar until well blended .
Add egg, and beat well.
Combine dry ingredients and fold into creamed mixture.
Add apples and cheese until just moistened.
Spoon into greased and floured 8- inch square pan and bake for 45 minutes.
Cool on rack, then sprinkle with confectioner's sugar.
Serve with warm vanilla sauce.