Heat oven to 350°F (175°C). Using a baking spray with flour, evenly spray the bottom and sides of a 9-inch (23 cm) round baking pan; set aside.

In a medium bowl, whisk together flour, baking powder, cinnamon, baking soda, nutmeg and salt; set aside.

In a bowl fitted to an electric stand mixer with the paddle attachment, beat on medium to high speed brown sugar and butter until light and fluffy, about 1 minute.

Add eggs one at a time until well incorporated. Add apple butter and vanilla. Continue to mix on medium speed until just combined.

Reduce the speed of the electric mixer to low-medium and slowly add in the flour mixture alternating with the buttermilk and ending with the flour mixture. Continue to mix until just combined.

Spread batter into the prepared baking pan. Bake for 50 minutes or until a toothpick inserted in the center comes out dry with a few crumbs.

Leave cake in the pan to rest for 10 minutes before removing onto a wire rack to cool to room temperature.

Meanwhile, prepare the apples. Cut apples into ½-inch (1.3 cm) thick wedges.

In a large bowl, toss apples with brown sugar, cornstarch, cinnamon and salt.

In a large skillet over medium heat, melt butter and sauté the apples until softened and golden in color.

Remove from heat.

In a small saucepan over medium heat, bring brown sugar, butter, heavy cream and salt to a boil for 1 minute, stirring constantly.

Remove from heat and stir in bourbon and powdered sugar until smooth.

Beginning from the outer edge of the cooled cake, create a ring of sautéed apple slices slightly overlapping each slice with the next one.

Continue to create additional rings of apples working towards the center. Ideally, use any small slices in the center.

Drizzle bourbon caramel sauce over the apples. Cut and serve immediately.