Making the Chocolate Pound Cake

1. Preheat the oven to 160°C (fan)/350℉.
2. In a bowl, mix cocoa powder with boiling hot water and stir until fully dissolved. Set aside to cool.
3. In a large bowl, sift together cake flour, baking powder, and salt. Stir to combine.
4. Beat the unsalted butter at medium speed until light and fluffy. Add the sugar and continue beating until pale and creamy.
5. Add eggs one at a time, mixing for 10–20 seconds between each addition to ensure they are fully incorporated. Then mix in vanilla extract.
6. Ensure the cocoa mixture has cooled before adding it to the batter to prevent curdling.
7. Add the flour mixture and milk alternately, starting and ending with the dry ingredients. Mix until smooth.
8. Evenly divide the batter between two lined baking pans, each pan should have around 750 g of batter.  Smooth the surface with an offset spatula.
9. Bake in a preheated oven for 30–35 minutes, or until a skewer inserted in the centre comes out clean.
10. Let cakes rest in the pan for 15 minutes before transferring to a wire rack to cool completely.

Making the Chocolate Mascarpone Frosting

1. Sift together icing sugar, cocoa powder, and salt in a mixing bowl.
2. Add vanilla extract to double cream.
3. Beat mascarpone cheese at medium speed for 30 seconds until slightly fluffy.
4. Add the cocoa powder mixture and gently mix with a spatula before beating until well incorporated.
5. Pour in the vanilla-infused double cream and beat until the frosting is light, fluffy, and smooth. Refrigerate until needed.

Frosting the Cake

1. Level the cakes by trimming off the domed tops. Place one layer on a cake board and spread enough frosting and spread it as evenly as you can. 
2. Place the second cake layer upside down for a flat top.
3. Apply a thin layer of frosting to seal crumbs, then chill the cake until firm.
4. Pipe and spread an even layer of frosting over the entire cake. Smooth the sides and top with an offset spatula and dough scraper.
5. Refrigerate for 60 minutes before applying the ganache.

Making the Chocolate Ganache

1. Combine chopped dark chocolate with double cream in a microwave-safe bowl.
2. Microwave for 20 seconds, stir, then continue in 5-second bursts until smooth.
3. Test by drizzling in a bowl; it should stop flowing after a few seconds. (see note 1)
4. Load into a piping bag, snip a small hole, and drizzle around the cake’s edges before spreading the rest on top.

Optional: Fondant Decorations

1. Have a cutting mat, fondant, icing sugar for dusting, a rolling pin, and a template.
2. Knead and roll out fondant, then cut out shapes with a cutter or knife. (see note 2)
3. Use a tiny amount of water to stick fondant pieces together.