Preheat oven to 325 degrees. Spray an 9 inch round or square pan with cooking spray. Set aside.
In a medium saucepan melt 1/4 cup butter over medium heat until melted. Add the brown sugar. Bring it to a boil and remove from heat. Stir in 1/4 teaspoon of cinnamon. Pour into the bottom of the greased pan. Arrange the apples over the brown sugar mixture.
In a medium size bowl whisk together flour, baking powder, 1/2 teaspoon cinnamon and salt. Set bowl aside.
In a large bowl or mixer, beat together 1 cup sugar, and 1/2 cup butter on medium speed until fluffy. Add in eggs and vanilla.
Beat in flour mixture alternating with the milk until smooth. Pour the batter over the apples and spread evenly.
Bake 55-60 minutes or until toothpick comes out clean. Cool on a wire rack for 15 minutes.
Meanwhile, to make the whipped topping, beat whipping cream on high until soft peaks start to form. Add in 2 tablespoons sugar.
Run knife along the edges of the cake and flip upside down on a pan. Serve warm with whipped cream on top.