Preheat oven to 350°F. Generously grease a round 9-inch baking pan.

Melt 1/4 cup butter and 2/3 cup brown sugar in small sauce pan over medium heat, stirring until smooth.

Pour into prepared pan. Arrange apple slices on top of caramel so they slightly overlap.

To make the cake, combine 1 1/2 cups flour, 1 tsp baking powder, 1/2 tsp cinnamon, 1/8 tsp nutmeg and 1/4 tsp salt in a small bowl; set aside.

Beat 1 cup softened butter and 1 cup sugar on medium high speed with an electric mixer until pale and creamy, about 3 minutes. Add 2 eggs, one at a time, mixing after each; mix in 1/2 tsp vanilla.

Add flour mixture in 3 additions, alternating with milk, and ending with flour mixture; mix until just combined.

Pour batter over apple slices and gently spread into an even layer.

Bake cake until top is golden brown and center springs back when gently pressed, about 45-55 minutes.

Let cake stand about 10 minutes. While cake is still warm, run a knife around edges and invert onto a plate or cake stand.

To make the caramel sauce, combine 1 cup brown sugar, 1/2 cup butter, 1/4 cup milk, 1 tsp vanilla and 1/4 tsp salt in medium saucepan over medium heat. Bring to a boil and simmer 3-4 minutes, stirring often, until caramel is smooth and thickened.

Drizzle caramel sauce over sliced cake before serving. Enjoy!