Caramel Apple Topping:
- 1/4 cup butter
- 2/3 cup packed brown sugar
- 2 apples, thinly sliced
- 1/2 cup butter softened
- 1 cup granulated sugar
- 2 eggs
- 1/2 tsp vanilla
- 1/4 cup milk
- 1 1/3 cup all-purpose flour
- 1 tsp baking powder
- 1/2 tsp ground cinnamon
- 1/4 teaspoon salt
- Preheat the oven to 325 F/162 C. Adjust the rack to the middle of the oven. Line a 9-inch square pan with parchment paper.
- Make the caramel by melting ¼ cup butter in a medium saucepan over medium heat. Add the brown sugar and bring it to a boil. Remove from the heat and immediately pour into the prepared pan.
- Arrange the apple slices on top of the caramel, overlapping slightly.
- Make the cake by beating ½ cup butter with granulated sugar with a mixer until fluffy. Add the eggs, one at a time, and beat until smooth. Pour in the vanilla and the milk and beat to combine.
- Mix together the flour, baking powder, cinnamon, and salt in a medium bowl. Add the flour mixture to the egg mixture and beat until smooth.
- Spread the cake batter over the apple slices, making sure the batter goes all the way to the edges of the pan to cover the apples completely.
- Bake at 350 for 45 to 55 minutes or until a tester inserted into the center comes out clean.
- Remove from the oven and let cool on a wire rack for 15 minutes. The cake should still be warm before flipping.
- Place a serving plate or platter on top of the pan. Using both hands, flip the plate and the cake pan upside down together. Remove the pan and carefully peel back the parchment. Let it cool to room temperature before slicing and serving.