Preheat your oven to 350°F (175°C). Grease and flour a 9-inch (23cm) round springform pan, or line the bottom with parchment paper and grease the sides.

In a medium bowl, combine the diced apples, light brown sugar, and lemon juice. Toss gently to coat the apples and set aside.

In a separate medium bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, ground cinnamon, and ground nutmeg. Set aside.

In a large mixing bowl, using an electric mixer on medium speed, cream together the softened butter and granulated sugar until light and fluffy, about 3-4 minutes.

Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

Gradually add the dry ingredients to the wet ingredients in three additions, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix on low speed until just combined after each addition. Be careful not to overmix.

Pour half of the cake batter into the prepared springform pan, spreading it evenly. Arrange about half of the apple mixture over the batter.

Carefully spoon the remaining batter over the apples, spreading it gently to cover. Top with the remaining apple mixture.

Bake for 50-60 minutes, or until a wooden skewer or toothpick inserted into the center of the cake comes out clean. The top should be golden brown and the edges slightly pulled away from the pan.

Let the cake cool in the pan on a wire rack for 15-20 minutes before carefully removing the springform sides. Allow the cake to cool completely on the wire rack before slicing.

Once cooled, dust generously with powdered sugar before serving. Serve plain or with a dollop of whipped cream or custard.