FOR THE CARAMEL

1. Add the sugar, water, and corn syrup to a heavy bottomed medium saucepan. Mix to combine. Cook over high heat, without stirring, until the mixture becomes a dark amber color, about 14 minutes. Don’t walk away! Remove from the heat and carefully add the cream. Be careful…it will splatter! Stir until it’s smooth.
2. Clip a candy thermometer on the side of the pan. Return the pan to medium-high heat, and cook until the caramel reaches 238 degrees, (soft-ball stage). Remove from heat, and mix in the salt. Allow the caramel to cool for 15 minutes.
3.  Add the butter a couple of pieces at a time, mixing it into the caramel each time. Allow the caramel to cool completely while you make the cake. You can also make the caramel in advance. Refrigerate it and bring it to room temperature before using.

FOR THE CAKE

1. Preheat oven to 350 degrees.
2. Butter the insides of three 9-inch round cake pans. Cut and fit a piece of round waxed or parchment paper to place in the bottoms of each pan. Butter the paper. Dust the paper and the insides of the pans generously with cocoa powder, tapping out any excess.  Set aside.
3. Over the bowl of a stand mixer, sift the flour, granulated sugar, cocoa, baking soda, baking powder, and salt. Note…if the holes in your wire mesh strainer are really small, the salt will remain in the sifter. Just add it back into the bowl after sifting. Beat on lowest speed until all ingredients are combined. Increase speed to medium and add the eggs, one at a time, making sure each one is incorporated before adding the next one. Add buttermilk, oil, vanilla, and warm water. Beat on medium speed until the mixture is very smooth and free of any lumps, about 1 minute. Don’t over beat it.
4. Divide the batter equally between the three pans. You should have roughly 1 1/2 cups or 12 ounces of batter per cake pan. Mine was actually 14 ounces per pan to be exact.  Shake them back and form to level out the batter and tap each pan on a counter to pop any air bubbles.
5. Bake the cakes until a toothpick inserted in the centers comes out clean, about 35 minutes.  Let the cakes cool in the pans for 10 minutes. Run a sharp knife around the edges and invert cakes onto wire racks to cool completely.
6. Trim the mounded tops of the cake layers to make them level. (Go ahead and sneak and eat that part, when the kids aren’t watching). It’s best to use a serrated knife. Cut each cake layer horizontally to form 2 thinner layers.

FOR THE FROSTING

1. In a measuring cup, whisk together the cocoa and 1/4 cup plus 2 tablespoons of warm water, making a slurry. Set aside.
2. To the bowl of a stand mixer, add the butter, powdered sugar, and salt, and beat on medium speed until light and fluffy. Gradually beat in the melted chocolate followed  by the cocoa slurry. Beat until well combined.  Set the frosting aside for 30 minutes before using.
3. Assemble the cake: Transfer 1 split cake layer to a cake plate. Spread about 3/4 cup of the caramel over the layer. Repeat with remaining layers, not covering the top one. Refrigerate the cake for 1 hour before frosting.
4. Frost the top and sides of the cake. Sprinkle a little bit of coarse salt on top.
5. Cover the cake, (I place it in my cake container), and leave it at room temperature for up to 3 days.