Preheat & Prep: Start by preheating your oven to 350°F. Grease and flour two 8- or 9-inch round cake pans, or four 8×1-inch pans if you prefer thinner cake layers. This step helps ensure the cakes release cleanly after baking.
Dry Ingredients: In a large mixing bowl, whisk together the cocoa powder, all purpose flour, granulated sugar, baking soda, baking powder, and salt until fully combined. Mixing the dry ingredients well helps the cake bake evenly.
Wet Ingredients: Add the eggs, buttermilk, vegetable oil, vanilla extract, and butter flavoring to the dry mixture. Mix on medium speed just until incorporated. The batter will be thick at this stage, which is normal.
Bloom Cocoa: Slowly pour in the boiling water while mixing on low speed. This step blooms the cocoa powder and intensifies the chocolate flavor, creating a smooth and pourable batter.
Bake Layers: Divide the batter evenly between the prepared cake pans. Bake for 20 to 25 minutes, or until a toothpick inserted in the center comes out mostly clean.
Cool & Chill: Let the cakes cool in the pans for 10 to 15 minutes, then turn them out onto a wire rack to cool completely. For easier handling and clean layers, freeze the cake layers for 4 to 6 hours or overnight.
Buttercream Base: Beat the butter until completely smooth and creamy. This creates the foundation for a light, fluffy caramel buttercream frosting.
Sweeten & Flavor: Add half of the powdered sugar and half of the caramel sauce, mixing until combined. Then add the remaining powdered sugar, the rest of the caramel sauce, and the salt. Beat on high speed for 5 to 7 minutes until light and fluffy.
Prepare Piping: Transfer about half of the buttercream into a piping bag or zip-top bag and snip off the tip to make cake assembly easier and cleaner.
Layering: Place the first cake layer on a serving plate. Pipe a buttercream dam around the inside edge, then spread a thin layer of buttercream inside the dam if desired. Spoon caramel sauce over the center and gently spread it out. Repeat with the remaining layers.
Final Frosting: Frost the outside of the cake with the remaining caramel buttercream. Smooth the sides and create a simple zigzag pattern on top using an offset spatula or spoon.
Serve & Enjoy: Slice and serve your chocolate caramel cake right away, or chill briefly to help the layers set. Enjoy!