Preheat your oven to 325 degrees F. Spray three 8-inch or four 6-inch round cake pans with cooking spray and then line with parchment paper. Spray again. Set aside.

In a stand sized mixer fitted with the paddle attachment, combine the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Mix on low until evenly combined.

In a small bowl, whisk the eggs, buttermilk, hot water, vanilla extract, and vegetable oil until evenly combined.

With the mixer on the lowest speed, pour the liquid ingredients into the dry ingredients and mix just until combined. There should be no flour streaks. With a rubber spatula, scrape the bottom of the bowl to make sure the batter is evenly combined.

Divide the batter evenly between the prepped pans (about 15 ounces in each 8 inch pan) and bake for 30-33 minutes. After they are done baking, let them cool for 15 minutes in the cake pans and then transfer them to a cooling rack and let them finishing cooling there.

After the cakes have come to room temperature, level the tops of the cakes, if needed, and then wrap them in plastic wrap and freeze them in preparation for frosting the cake.

In a medium sized sauce pan, stir together the water, sugar, and corn syrup.

On medium heat, bring the sugar to a boil. The bubbles will start off fast and small, but once it starts caramelizing, the bubbles will slow down and become a little bigger. Do not touch or stir the mixture. That will cause crystallization.

Let the mixture boil until it becomes caramelized and looks golden brown. This does take a few minutes, but once it starts turning brown, it’s easy to burn it, so keep an eye on it.

Put the cream in the microwave for 1 minute.

Once the caramel is ready for the cream, turn off the heat on the sugar mixture and add the warm cream. Mix the caramel mixture until evenly combined.

Pour the mixture into a bowl. Add the vanilla, salt, and butter and let it sit until the butter melts. Stir once the butter is melted.

In a bowl fitted with a paddle attachment, beat the butter on medium-high speed for about 4 minutes. It should soften a little, but also still be slightly stiff.

Add the caramel sauce and mix on medium speed for 60 more seconds.

Add the sifted powdered sugar, vanilla extract, salt and heavy cream. Mix on low. Once incorporated, beat on medium for 4-5 minutes.

Before frosting your cake, use a wooden spoon or rubber spatula to hand mix the frosting to push out any air bubbles.

With a piping bag, pipe a small dollop of frosting onto a cake board. Place the first chocolate cake layer, top side up, onto the board.

Evenly spread about ¼ cup of the caramel buttercream on top of the cake layer.

Pipe a rim of frosting around the edge of the buttercream to create a barrier for the filling.

Spread about ¼ cup of the caramel sauce in the center of the cake. With the back of a spoon, carefully spread it to the edge of the piping.

Place a second cake layer on top of the piped frosting and filling and repeat the steps for the first layer. Place the final cake layer, top side up, on the second layer of filling.

Frost a thin coat of frosting around the cake to lock in the crumbs. This is the crumb coat. Freeze the cake for about 10 to 15 minutes to set the frosting.

Finish frosting and decorating the cake with the remaining caramel buttercream. Serve with the remaining caramel sauce.