• Preheat the oven to 325 degrees F. Grease and Flour three 8 inch round pans. As an optional step, we also like to line the bottom of our pans with parchment paper.
• In the bowl of your mixer, add the chocolate cake mix, all purpose flour, sugar, and chocolate pudding mix. Whisk to blend.
• Add the remaining ingredients to the bowl (sour cream, vegetable oil, water, eggs, and vanilla). Mix on low speed for about 30 seconds.
• Scrape down the sides and bottom of the bowl as needed and mix on medium speed for two minutes. The batter should look well blended.
• Bake at 325℉ for approximately 20-25 minutes or until the layers spring back when lightly touched, or a toothpick can be inserted and removed with just a few moist crumbs attached. Baking times may vary depending on your oven and the type of pans used. Dark pans may bake slightly more quickly.
• Allow the baked cake layers to cool in their pans on a wire rack for 10 minutes before turning out. Make sure that they are completely cool before frosting!

Caramel Cream Filling

• Combine the sifted vanilla pudding mix and heavy cream in a mixing bowl. I prefer to mix with a hand held mixer. If you don't have one, you can use a whisk, or the whisk attachment of a stand mixer.
• Mix on low to medium speed until well combined and it begins to thicken. Then, add the caramel sauce. Mix on medium-high speed. The mixture will become thick and fluffy. You can add an additional tablespoon or two more if needed.
• This makes about two cups of caramel cream filling.

Chocolate Buttercream

• Add butter and mix on low to medium speed until smooth. Add vanilla and blend into the butter.
• Add powdered sugar, salt, and cocoa powder.
• Add most of the milk and mix on low speed, increasing to medium as the ingredients become incorporated.
• Continue to mix adding remaining milk as needed. It may take 3-5 minutes to reach the smoothness and consistency you like. It will take longer if using a hand mixer. As you mix, the frosting will become very smooth. You can add additional milk (1 Tablespoon at a time) if the frosting is too thick or additional powdered sugar if too soft.

Assembling and Decorating the Cake

• Place the first chocolate cake layer on the cake base or pedestal. Next, spoon some chocolate frosting into a disposable piping bag with the tip snipped away. Then, pipe a fairly thick ring of buttercream about ¼ inch from the edge of the cake layer. This is a dam that will keep your filling contained.
• Next, poke some shallow holes into the top of the cake layer, followed by a thin layer of caramel sauce.
• Next, because of the slick surface of the caramel-glazed cake, it is best to pipe on the caramel mousse filling using a disposable piping bag with the tip snipped away. Then, use an offset spatula to lightly spread over it.
• Top with the second cake layer and repeat. Top with the third cake layer and fill in any remaining gaps between the cake layers with chocolate buttercream.
• Crumb coat the top and sides of the cake with a thin layer of buttercream. At this point, we like to chill the cake in the freezer for 15 minutes or in the refrigerator for longer, to firm everything up. Then, add the final layer of buttercream and decorate to your liking.
• We added texture with a small offset spatula, and then piped a top border with our remaining filling and frosting (using a star piping tip 21.) I piped two reverse shell borders.
• This cake should be refrigerated because of the filling. However, for best flavor and texture, it is best to remove the cake from the refrigerator a couple of hours before serving.