Preheat your oven to 350°F (175°C). Grease and flour three 9-inch round cake pans.

In a large mixing bowl, combine the flour, sugar, cocoa powder, baking powder, and salt.

In another bowl, whisk together the brewed coffee, buttermilk, vegetable oil, and eggs. Gradually add the wet ingredients to the dry ingredients and mix until smooth.

Divide the batter evenly among the prepared pans and bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

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

To prepare the buttercream frosting, beat the softened butter in a mixing bowl until creamy.

Gradually add the powdered sugar, heavy cream, and vanilla extract, beating for 5 minutes until light and fluffy. If the frosting is too thick, add a little more heavy cream to reach your desired consistency.

Assemble your cake by placing one layer of the cooled cake on a serving plate or cake stand.

Spread a layer of buttercream frosting on top, then repeat with the second layer, adding more frosting.

Place the third layer on top and frost the top and sides of the cake with the remaining buttercream.

Drizzle the cooled caramel sauce over the top of the frosted cake, allowing it to drip down the sides for a beautiful presentation.