Arrange a rack in the middle of the oven and preheat the oven to 350 degrees Fahrenheit. Coat the inside of a 9-inch springform pan with cooking spray or butter. You can also use a regular 9-inch baking cake pan lined with a parchment paper circle and greased with cooking spray or butter.
Whisk together the flour, baking powder and salt in a mixing bowl.
You can mix the cake batter by hand, with a handheld electric mixer or with a stand mixer with the paddle attachment. Beat the butter and granulated sugar on medium-high speed for about 3 minutes or until light and fluffy.
Add the eggs one at a time, allowing each to incorporate before adding the next one. Scrape down the sides and the bottom of the bowl with a rubber spatula as needed. Add the vanilla and the calvados or rum and mix to combine. The batter may look grainy at this point.
With the mixer on low speed, add the flour mixture and mix until just combined.
With the help of a spatula, fold in the chopped apples and mix to combine. The batter will be thick.
Transfer the batter to the prepared pan. You can smooth the top a bit with a spatula. Sprinkle the top with granulated sugar (about a tablespoon).
Bake for about 40 minutes or until a cake tester or wooden skewer inserted into the center of the cake comes out clean. Transfer the cake pan to a cooling rack and cool for about 30 minutes. Run a knife around the edges of the cake and if using a springform pan, remove the sides. If using a regular baking pan, turn it out onto a cake plate or wire rack and remove the parchment paper.
Using a fine sieve, dust the cake with confectioners’ sugar (optional). The cake can be served warm or at room temperature.