CHOCOLATE MUD CAKE

1. Preheat the oven to 350˚f / 180˚c. Grease and line three six inch cake tins.
2. Mix the milk and lemon juice together, and set aside. 
3. In a medium pot, combine the chocolate, oil, vanilla and coffee. Heat over low heat, stirring constantly, until the mixture is melted and smooth. Remove from the heat and allow to cool slightly. 
4. In a large bowl, whisk together the flour, baking soda, baking powder, sugar, salt, and cocoa powder. 
5. Add the milk mixture to the cooled chocolate mixture along with the eggs, and mix well to combine. Add the wet ingredients to the dry ingredients, and mix until well incorporated. 
6. Divide the mixture between the three prepared tins. Bake for 40 to 45 minutes, or until a cake tester inserted in the middle of a cake comes out with a few crumbs attached. 
7. Remove from the oven, and allow to cool in the tins for 15 minutes. Remove from tins and cool completely on a wire rack. Level the cakes off, wrap tightly in plastic wrap, and store in the fridge or freezer until ready to use.

SALTED CARAMEL

1. Place the sugar in a medium sized heavy bottom saucepan. Heat on medium, stirring constantly. The sugar will start to form clumps, then begin to melt. Cook until is it amber in colour, then remove from the heat and immediately add all of the butter. Be careful as the caramel will bubble rapidly. Once the butter is incorporated, add the cream and stir well. Stir in the salt, and pour into a glass jar. Allow to cool completely.

MASCARPONE GERMAN BUTTERCREAM

1. In a bowl, whisk together the sugar, corn starch, egg, egg yolk and salt. In a medium non-stick saucepan, heat the milk and vanilla to just shy of a simmer. Remove from the heat.
2. Using one hand to whisk constantly, pour half of the hot milk mixture into the egg mixture. This helps to temper the eggs and stop them from scrambling. Whisk until incorporated, and then pour the whole lot back into the saucepan. 
3. Heat the milk and egg mixture over medium heat, whisking constantly, until it begins to bubble. It will thicken quickly. Once it has thickened, cook for one minute, then remove from the heat. Pour into a shallow dish or bowl of a stand mixer and press some plastic wrap over the surface to avoid a skin from forming. Refrigerate until cold. If you are in a hurry, you can speed up this process by placing the custard mixture into a bowl, and placing the bowl into an ice bath, stirring frequently.
4. Fit your mixer with the whisk attachment. Whip the custard mixture on medium until creamy and lump-free. Begin adding the butter, a few cubes at a time, until fully incorporated. Add the Mascarpone and mix to incorporate. Switch to the paddle attachment and beat for a few minutes until smooth and silky. 

ASSEMBLY

1. Place the first levelled layer on a cake stand or turntable. Top with a generous amount of the german buttercream, and smooth out with an offset spatula, building more buttercream around the sides than in the centre of the cake. Fill the centre with about ⅓ of the cooled salted caramel (this amount may vary depending on preference), and top with the second layer. Repeat the buttercream and caramel process, then top with the third layer. 
2. Smooth an rough layer of buttercream all over the top and sides of the cake using an offset spatula, and smooth using an icing smoother. You can go for a fully covered effect, or leave it semi naked as I did. Place in the fridge for 20 minutes to chill. While the cake is chilling, divide the remaining buttercream between four bowls, and colour each various shades of pink using gel food colouring. Transfer each colour to a piping bag fitted with a french star tip. 
3. Remove the cake from the fridge. Apply gold leaf if desired. Pipe blobs of buttercream randomly all over the cake, arranging as desired. 
4. Allow to come to room temperature before serving.
5. Store Leftovers in the fridge.