1. Preheat your oven to 350°F (175°C). Grease and line three 8-inch round cake pans with parchment paper.

2. Sift together flour, cocoa powder, baking powder, baking soda, and salt in a large bowl.

3. In another bowl, whisk together granulated sugar, brown sugar, eggs, milk, sour cream, vegetable oil, and vanilla until well combined.

4. Gradually add the dry ingredients to the wet mixture, then pour in the hot water or coffee slowly while stirring. Batter will be thin.

5. Divide batter between the pans and bake for 28–32 minutes. Let cakes cool in pans for 10 minutes, then transfer to wire racks to cool completely.

6. For the frosting, melt dark chocolate with butter over a double boiler. Let cool, then beat until creamy. Gradually add powdered sugar and a little cream until spreadable. Add vanilla to finish.

7. Frost the cake by layering with generous amounts of fudge frosting between each layer and around the sides.

8. Heat cream until simmering, pour over chopped chocolate to make ganache. Stir until glossy, let cool slightly, then pour over cake.

9. Garnish with chocolate curls, fresh mint, or edible gold leaf. Chill at least 1 hour before slicing.