Preheat your oven to 350°F (175°C). Line two 8-inch round cake pans with parchment paper and grease them lightly with baking spray for easy release.

In a medium-sized bowl, whisk the Dutch-processed cocoa powder with hot brewed coffee until fully dissolved and smooth, ensuring no lumps remain. Incorporate the warm melted chocolate and whisk until well-blended. Set this mixture aside to cool slightly.

In another bowl, combine the all-purpose flour, baking powder, baking soda, and salt. Whisk until these dry ingredients are thoroughly mixed.

In a large bowl, whisk together the eggs, white sugar, sour cream, vegetable oil, and vanilla extract until smooth and creamy. Slowly pour in the cocoa-coffee-chocolate mixture and whisk until everything is silky and well-combined.

Gradually add the dry ingredients to the wet mixture, stirring until the batter is smooth and fully incorporated.

Divide the cake batter evenly between the prepared cake pans. Bake for 40-45 minutes, or until a toothpick inserted into the center of each cake comes out clean. If the cakes are not done, bake for an additional 5 minutes and test again.

Let the cakes cool in their pans for about 30 minutes. Once cooled, gently remove them from the pans and transfer to a wire rack to finish cooling completely.

In a large bowl or the bowl of a stand mixer, beat the softened butter together with the sifted confectioners' sugar and cocoa powder. Mix on medium speed for about 2 minutes until the mixture becomes fluffy and well-combined.

Gradually add the warm cream while continuing to beat until the frosting is smooth. Pour in the melted chocolate and vanilla extract, then beat again for about 2 minutes until the frosting is rich, fluffy, and smooth.

For a firmer texture, cover the surface of the frosting with plastic wrap and refrigerate for 30-45 minutes before using.

Once the cake layers are completely cooled, level the tops with a knife if necessary to create a flat surface.

Place the first cake layer, top side down, onto your cake stand. Spread a generous amount of frosting over the surface using an icing spatula.

Place the second cake layer on top, then frost the entire cake—sides and top—with the remaining frosting, smoothing the surface with a bench scraper for a clean finish.