1-Preheat oven: Preheat the oven to 350°F (175°C).

2-Prepare cake pans: Grease two 8-inch round cake pans and line with parchment paper.

3-Bloom cocoa: Whisk half of the cocoa powder with the hot coffee in a small bowl.

4-Mix dry ingredients and wet: In a large bowl, sift flour, remaining cocoa, sugar, baking soda, baking powder, and salt; then add eggs, buttermilk, vegetable oil, and vanilla, and whisk until smooth.

5-Add bloomed coffee: Pour in the bloomed coffee mixture and stir until just combined.

6-Divide batter: Divide the batter evenly between the prepared pans.

7-Bake cakes: Bake for 30-35 minutes, until a toothpick inserted in the center comes out clean.

8-Cool cakes: Let cakes cool in pans for 10 minutes, then turn out onto a wire rack to cool completely.

9-Start frosting: Chop semi-sweet chocolate and place in a saucepan with butter, heavy cream, and sifted powdered sugar.

10-Melt mixture: Set over lowest heat, whisking constantly until chocolate melts and sugar dissolves; do not boil.

11-Strain frosting: Once smooth, pour through a fine mesh strainer into a shallow square pan to remove air bubbles.

12-Chill frosting: Refrigerate, stirring occasionally, until frosting thickens to a spreadable consistency, about 30-45 minutes.

13-Assemble first layer: Place one cooled cake layer on a serving plate and spread a generous layer of chilled fudge frosting on top.

14-Assemble second layer: Place the second layer on top, press gently, then cover the entire cake with remaining frosting, smoothing with an offset spatula.

15-Rest before slicing: Let the assembled cake sit at room temperature for 15 minutes before slicing.