Preheat oven to 350 degrees F and grease two 9 inch round cake pans, and sprinkle each pan with 1 Tb of flour.
Mix cake mix, pudding mix, eggs, milk, sour cream, oil, and vanilla together for ONE minute. Do not over beat as it will result in lumpy cake.
Divide evenly into the two 8 or 9 inch round pans. Bake for 30-35 minutes or until inserted toothpick comes out clean. Let cool completely and refrigerate before frosting, at least 2 hours or overnight.
For the Dulce de Leche Cream Cheese Frosting:
Cream the butter and cream cheese until light and fluffy then add in the vanilla. Add the powdered sugar in ½ cup intervals, mixing between each addition, then beat in 1/2 cup of the dulce de leche until fully combined.
Assemble the Cake:
Once cakes are chilled, frost the top of one cake with a layer of dulce de leche frosting. Spread the other cake top with 1/2 cup of dulce de leche caramel and layer the cakes together so that the caramel and frosting are together between the cakes (like a peanut butter and jelly sandwich.)
Frost the outside and top of entire layered cake with chocolate frosting. Decorate with dulce de leche frosting as you see fit. Drizzle top of cake with dulce de leche caramel and sprinkle with heath bar toffee bits. Enjoy!