Preheat oven to 350 degrees F. Line a 13x9" baking pan with foil, extending the sides of the foil over the edges of the pan. Spray the foil with cooking spray and set aside.

In a large bowl, combine the spice cake mix, egg and melted butter until a thick dough forms. Press the dough evenly into the prepared pan; set aside.

In the bowl of a stand mixer, cream together the cream cheese, apple butter and brown sugar until smooth, about 1 minute. Add in the vanilla extract, apple pie spice and eggs, one at a time, mixing well after each addition. Add in the box of powdered sugar, mixing well, followed by the melted butter. Beat until mixed together.

Pour the apple butter filling on top of the crust and bake for approximately 35-45 minutes or until just about set. The center will be slightly jiggly - that's okay as it will continue to set up as it cools. If the center is sloshing around, bake it for a little longer using 5-minute increments.

Cool the bars completely, then refrigerate for at least 2-3 hours or until set. Cut into bars and drizzle with caramel sauce or dulce de leche before serving.