Step 1

Start by pre-heating your oven to 180c. Also grease and line two 8 inch cake tins.

Step 2

In a large bowl, add the cocoa powder, coffee and the hot water. Whisk these together.

Step 3

Now add the oil, buttermilk and eggs. Whisk all this until combined.

Step 4

Add the flour and both sugars, whisk just until you get a smooth batter.

Step 5

In a small separate bowl, add the baking soda and pour the vinegar over this. This will start bubbling, just give it a quick mix and then add it into your batter and whisk this in.

Step 6

Pour this batter into your prepared cake tins, then bake in your pre-heated oven for around 35-40 minutes, or until a toothpick inserted into the centre comes out clean.

Step 7

Once baked, leave to cool completely.

Step 8

Start by lining the sides of a tall loose bottomed or springform cake tin. You can either do this with baking paper or acetate.

Step 9

In a large bowl, add the double cream. Whip this on high speed until you get firm peaks. Leave this in your fridge until ready to use.

Step 10

In a separate large bowl, add the egg whites. Start whipping this, then once the egg whites become foamy, start pouring in the granulated sugar whiles still whipping.

Step 11

Once all the sugar has been added, whip until you get stiff peaks. Leave this in your fridge too.

Step 12

In a final large bowl, add the dark and milk chocolate. Place this into your microwave and heat in 15 seconds intervals, until all the chocolate has melted.

Step 13

Add the egg yolks and salt into this, whisk these in. This mixture will become super thick, don't worry this is expected.

Step 14

Add a large dollop of your whipped cream into this and whisk this in, to loosen up the mixture. Then add the rest of the whipped cream and fold this in gently.

Step 15

Add half of the whipped egg whites into this, gently fold these in. Now add the remaining whipped egg whites and fold these in until you can no longer see any lumps or streaks of the egg whites.

Step 16

Start by cutting the tops of your cooled cake layers off, just so we have more flat even layers.

Step 17

Place one of these layers into your prepared loose bottomed/springform cake tin.

Step 18

Add the chocolate mousse on top of this and spread it out. Place this in your freezer for 20 minutes.

Step 19

Whiles that is chilling, make the white chocolate mousse.

Step 20

We are making this the exact same way, but just with white chocolate instead. So follow the same steps, but use white chocolate. And then I also mixed in some vanilla once the mousse was made.

Step 21

Once your cake has chilled in your freezer for 20 minutes, take it out and add the white chocolate mousse on top of it.

Step 22

Now add the final chocolate cake layer on top.

Step 23

Leave this in your fridge to set up overnight.

Step 24

The next day, take the cake out of the tin. Then you can cut into it and enjoy!