Set your oven to 350°F (175°C). Grease two 8-inch round cake pans and line the bottoms with parchment paper to ensure the cakes release easily after baking.

In a small bowl, mix the cocoa powder with boiling water until it forms a smooth, lump-free paste. Allow it to cool slightly. In a separate bowl, whisk together the eggs, milk, and cooled cocoa mixture until fully combined.

Sift the flour, baking powder, and salt into a large mixing bowl. Add the softened butter and sugar, and mix until the texture resembles coarse crumbs. Gradually pour in the cocoa and egg mixture, stirring until the batter is smooth and well blended.

Divide the batter evenly between the prepared pans and smooth the tops using a spatula. Bake for 25–30 minutes, or until a toothpick inserted into the center comes out clean. Allow the cakes to cool in their pans for about 10 minutes, then transfer them to a wire rack to cool completely.

Whip the heavy cream until soft peaks form. Dissolve the coffee granules in hot water, then gently fold this into the whipped cream. Take care not to overwhip to maintain a light, fluffy consistency.

Place one cooled cake layer on a serving plate. Spread half of the coffee-flavored cream evenly on top. Add the second layer of cake, then spread the remaining cream over the top and around the sides for a smooth finish.

Dust the top of the cake generously with cocoa powder or drinking chocolate. Chill the assembled cake in the refrigerator for at least 30 minutes to set the cream before serving.