Preheat the oven to 350°F (180°C).
Grease an 8” springform pan with butter and dust lightly with flour. Or use a non-stick pan.
In a medium bowl, mix the flour with the baking powder and salt.
Using an electric mixer, cream the butter and sugar. Add the eggs and grappa, an mix until thoroughly combined. Add the flour mixture, and again, mix just until combined. Stir in the 2 chopped apples.
Pour the mixture into the prepared pan, and arrange the thinly sliced apple on the top. Bake for 30-40 minutes, until a skewer inserted in the middle comes out clean. Allow to cool for 15 minutes. Remove from the pan, sprinkle with confectioner’s sugar and cinnamon, and serve with whipped cream.