Apple Upside-Down Cake!

 4 T. butter, softened
¼ cup brown sugar
2 apples, peeled  and sliced
8 T. butter, softened
1 cup sugar
2 eggs
1 t. vanilla extract
½ c. yogurt
1½ c. flour
1 t. baking powder
½ t. baking soda
1/4 t. salt
1 T. cinnamon

Coat the bottom and sides of a 9 inch pie pan with 4 T .butter.  Sprinkle brown sugar over the butter.  Layer apple slices over the top in a circular pattern.  Beat 8 T. butter and 1 c. sugar until light and fluffy,  Add eggs, vanilla, and yogurt and mix until smooth.  Add flour, baking powder, baking soda, salt, and cinnamon and stir until just combined.  Pour the cake batter over the apple slices and bake at 350 degrees for 45 minutes or until fully cooked.  Let cool for 15 minutes.  Run a knife around the edge and invert the cake onto a large plate.  Let cool 10 minutes or more before serving.