In a large mixing bowl, stir 1 teaspoon cinnamon into the dry cake mix, then add ingredients called for on the package. Beat for 2 minutes with an electric mixer. Gently fold in chopped apple pie filling (I just used kitchen scissors and cut the apples right in the can). Pour into a greased 13x9-inch baking dish and bake cake in a preheated oven according to package instructions.

When the cake is done, remove from the oven and cool for 20 minutes.

Gently poke holes into the cake with the end of a wooden spoon or with the tines of a fork. The cake is very moist, so do this gently to avoid pulling it apart.

Pour the dulce de leche into a microwavable container and microwave in 20 second intervals, stirring each time, until thin enough to pour; about 1 minute.

Pour the dulce de leche over the cake and spread gently in an even layer.

Refrigerate cake for 4 hours or up to overnight.

Meanwhile, make the frosting. Beat butter and cream cheese on high speed for 2 minutes or until light and fluffy. Beat in powdered sugar, 1 teaspoon cinnamon and 1/2 cup caramel sauce. Beat for 1-2 minutes until smooth. Gently fold in whipped cream or cool whip. Add more as desired for a thicker consistency.

Drizzle with remaining caramel and sprinkle with optional chopped pecans or toffee bits. Refrigerate until ready to serve, then cut into squares.