Got a bushel of apples just waiting to be eaten? This idyllic fall dessert is inspired by a traditional German versunkener apfelkuchen, or sunken apple cake. The apples are baked until sweet and just tender while the buttery cake rises up around them. For a final sheen, we brush ours with an aromatic maple-bourbon glaze.
Pro Tip: You can make this cake in a well-greased, round 9-inch cake pan, but it will be much easier to remove if you have a 9-inch springform pan.
Preheat the oven to 350°F. Butter a 9-inch springform pan, then dust with flour, tapping out the excess.
In a medium bowl and using a fine-mesh sieve, sift the flour with the baking powder and salt. In the bowl of a stand mixer fitted with the paddle or using a hand mixer, beat the butter at medium-high speed until smooth and creamy, about 1 minute. Add the sugar and beat until light and fluffy, about 2 minutes.
At medium speed, add the eggs one at a time, beating well between each addition. Add the vanilla extract and lemon zest and beat until smooth, about 1 minute.
Reduce the speed to low and add half of the flour mixture until just combined, then add the milk, and then finish with the remaining half of the flour. Beat the cake batter until just combined, being careful not to overmix. The batter should be quite thick. Scrape the batter into the prepared pan and smooth the top.
Peel the apples, then cut them into quarters and remove the cores. Arrange the apple quarters flat side down on a cutting board. Using a very sharp knife, make thin parallel slices across each quarter, being careful not to cut all the way through. You want the apples to stay intact in one shingled piece. Arrange the apples on top of the batter, trimming them to fit if necessary (you may have a few extra pieces).
Bake the cake, rotating the pan halfway through baking, until the apples are just tender and the cake is a light golden brown, about 50 minutes (the apples will not be completely tender, but that’s intentional). Transfer the cake to a cooling rack and let cool for 15 minutes.
Make the glaze
In a small saucepan, combine the maple syrup and bourbon. Bring to a gentle boil, then reduce the heat to low and simmer, stirring occasionally, until the maple syrup has thickened slightly, about 5 minutes.
Remove the sides of the springform pan. Brush the maple-bourbon glaze all over the top and sides of the cake. Let the cake cool completely before transferring to a platter. Dust the apple cake with confectioners’ sugar, if using, and serve with whipped cream or vanilla ice cream.
MAKE AHEAD The cake can be stored covered at room temperature for up to 2 days.