Preheat your oven to 350°F and grease two 8-inch round cake pans. Line the bottoms with parchment paper to help the cakes release cleanly after baking.

In a large bowl, whisk together the flour, cocoa powder, sugar, baking soda, baking powder, and salt until evenly combined.

Add the eggs, buttermilk, vegetable oil, and vanilla extract to the dry ingredients. Mix until the batter becomes smooth and thick.

Slowly pour in the hot coffee while mixing gently. The batter will become thin, but this creates an incredibly moist and fudgy cake texture once baked.

Divide the batter evenly between the prepared pans and bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.

Allow the cakes to cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.

For the buttercream, beat the softened butter until smooth and fluffy. Gradually add the powdered sugar, mixing well after each addition.

Add the caramel sauce, heavy cream, vanilla extract, and sea salt. Continue beating until the frosting becomes creamy, light, and smooth.

To prepare the ganache, heat the heavy cream until steaming but not boiling. Pour it over the dark chocolate chips and let sit for one minute before stirring until glossy and smooth.

Place one cake layer onto a serving plate and spread a thick layer of salted caramel buttercream on top. Drizzle caramel sauce over the frosting and sprinkle lightly with flaky sea salt.

Add the second cake layer and frost the outside of the cake with the remaining buttercream. Chill the cake for about 20 minutes to help the frosting set before adding ganache.

Pour the dark chocolate ganache over the chilled cake, allowing it to drip naturally down the sides for a dramatic finish.

Decorate with chocolate crumbs, extra caramel drizzle, or chocolate curls if desired before serving.