Prepare the cake batter

1. Preheat the oven to 170℃ fan / 375℉ and line two 7-inch baking pans with parchment paper.   
2. Mix the cocoa powder into the piping hot coffee until fully dissolved. Set aside to cool. 
3. In a large mixing bowl, whisk the eggs, caster sugar, and light brown sugar vigorously until the mixture turns pale and thick.
4. Add the vegetable oil, whisking until the mixture is fully emulsified.  
5. Gently whisk in the plain yoghurt and vanilla extract until smooth and well combined.
6. Add the cooled coffee-cocoa mixture and whisk until everything is well incorporated. 
7. Sift the flour, baking soda, baking powder, and salt into the bowl. Mix well with a whisk until everything is fully combined.
8. Weigh the batter to divide it evenly into two portions (about 621 g each) and pour into the prepared pans.
9. Bake in a preheated oven at 170℃ / 375℉ for 30–35 minutes, or until a skewer inserted into the centre comes out clean.
10. Once done, remove the pans from the oven and let the cakes cool in the pans for 10–15 minutes. Then, unmold and transfer the cakes to a wire rack to cool completely.

Prepare the chocolate mascarpone frosting

1. Sift the icing sugar, cocoa powder, and salt into a mixing bowl. Mix well and set aside.
2. Stir the vanilla extract into the chilled double cream. Mix thoroughly and set aside.
3. In a large mixing bowl, place the chilled mascarpone cheese and add the icing sugar-cocoa powder mixture. Gently mix with a silicone spatula to prevent the powder from flying. Beat with an electric mixer on medium-low speed until well combined.
4. Gradually add the vanilla-cream mixture in two stages, pausing for 10 seconds in between to ensure smooth blending. Continue beating until the mixture forms a smooth, spreadable frosting.

Crumb coat the cake 

1. Place a non-slip mat on a turntable with a cake board on top.  Spread a little amount of frosting in the centre of the cake board to keep the cake in place.  Place a serrated knife on the side of the cake and cut while turning the turntable to trim off any dome on top to level it.   Once done, repeat the same process for the second layer.  
2. Spread a small amount of frosting in the centre of the cake board to stick the cake if needed.  Add the frosting to the first layer, I use an ice cream scoop to control the portion size.  Use an offset spatula to spread the frosting across the cake as evenly as possible.  
3. Place the second layered cake upside down on top of the frosting.  Scoop the same amount of frosting on top.  Use the offset spatula  to spread it across the cake as evenly as possible.  Gradually push / spread the excess frosting to the sides to fill any gaps or holes. 
4. Once done, place the cake in the refrigerator to chill for about an hour to set.  

Final coat

1. Load the remaining frosting into a piping bag.  Twist the end and secure with an icing bag tie.  
2. Once the frosting is set, place the chilled frosted cake on the turntable with a non-slip mat underneath. 
3. Cut a medium hole on the piping bag.  Pipe a layer of frosting on top of the chilled cake.  Gradually spread it into an even layer using an offset spatula.  Push any excess toward the sides and smooth out the frosting.  
4. Take a dough scraper and hold it at a 45-degree angle to the side of the cake, with a very light contact. Allow it to lightly brush the side of the cake as you spin the turntable.   If there are any holes or imperfections, spread a little more and smooth it again with the dough scraper. 
5. For the final smoothing, hold the dough scraper in one hand and spin the turntable with the other, gliding the scraper along the sides of the cake in one smooth motion.
6. To smooth out the top, take the offset spatula and glide over the top of the cake, starting from the edge and moving toward the centre.  
7. Once done, chill the cake for around 60 minutes to set.  

Decorate the cake

1. If you prefer to serve the cake on a cake stand rather than the cake board, use a spatula to carefully lift and transfer the cake onto your desired stand or serving plate.  
2. For this decoration, I used three different piping nozzles. To easily switch between them without making a mess, place a piping nozzle in a separate piping bag. Insert the frosting-filled bag into the piping bag, and pipe as desired. When you need to change the nozzle, simply pull out the frosting bag, switch the nozzle, and insert the frosting bag back in to continue decorating.
3. Add some gold chocolate balls on top to elevate the presentation. (optional)   
4. Enjoy a slice with a cup of coffee— absolutely delicious!