*To make your own apple pie spice, combine 12 g ground cinnamon, 6 g ground cardamom, 2 g fresh grated nutmeg, .6 g ground ginger, and .3 g ground allspice.
Preheat oven to 350ºF. Grease a 9-inch square or round baking pan, line it with crisscross sheets of unbleached parchment paper, greasing between the papers, and set aside.
In a medium bowl, place the apple purée, condensed milk, eggs, sugar, and apple pie spice. Beat until well combined. Add about half of the dry cake mix to the mixture. Mix to combine.
Pour half the mixture into the prepared pan. Lay apples over the mixture, and pour rest of mixture over the apples. Sprinkle the rest of the dry cake mix on top, smooth carefully until the cake mix covers the applesauce layer evenly. Pour the melted butter evenly on top of the cake. Next, sprinkle on a bit more apple pie spice and scatter a few dollops of applesauce on top of the cake. Cover the pan with foil.
Place cake in the center of the preheated oven and bake for 20 minutes. Uncover, and bake until the cake has begun to pull away slightly from the side of the pan and is set on top (10 to 12 minutes). Remove from oven and allow to cool completely before slicing into squares or wedges and serving.