
2. In a large bowl, whisk the brown sugar and eggs until pale and foamy, about 1 minute. Add the oil, vanilla, cinnamon, nutmeg, salt, and whiskey and espresso powder. Whisk until smooth and emulsified.
3. Add the flour, baking powder, and baking soda and whisk until well-combined and smooth.
4. Use a rubber spatula to fold in the apples and ¼ cup of the nuts.
5. Pour the batter into the prepared pan and use an offset spatula to gently smooth the top, making sure the apples are well dispersed and go all the way to the edges of the pan. Tap the pan gently on the counter to release any air bubbles. Sprinkle the remaining ¼ cup nuts over the cake.
6. Bake until puffed and golden, and a toothpick inserted into the center comes out clean, 30 to 35 minutes. Set the pan on a rack to cool for about 20 minutes. After that, unsnap pan and gently move cake to a wire rack to fully cool.
This cake is best served at room temperature or slightly warmed.