1. Set the oven to 375°F.
 2. Grease a 9-inch square baking dish with or pie pan a 4-cup capacity
 3. Sift the flour, baking powder, and salt.
 4. In a bowl, combine 1/2 a cup of the sugar with the cinnamon, set aside.
 5. In the bowl of an electric mixer, cream the butter with the remaining 1/2 cup sugar.
 6. Beat in the egg until blended.
 7. Add the flour mixture in three additions, alternating with the milk, beating until just combined.
 8. Spread half the batter in the baking dish.
 9. Lay the apple slices on the batter so they just cover the batter (you may have to overlap some slices).
 10. Sprinkle the apples with half of the cinnamon-sugar mixture.
 11. Spread the rest of the batter over the apples.
 12. Sprinkle the remaining cinnamon-sugar on top.
 13. Bake the cake for 25 minutes or until it is golden brown and apples start to bubble at the edges.