Step 1

Take two tablespoons of white sugar and put into a bowl along with the egg yolks, flour and cornflour – whisk to combine

Step 2

Put the remaining sugar into a suacepan with the milk and vanilla, slowly warm over a medium-low heat

Step 3

When it begins to get warm, drizzle a small amount of warm milk into the egg yolk mixture and whisk, then add a little more, repeat until everything is together in the bowl, then pour the whole mixture back into the saucepan. It's important to do this slowly and gradually so you don't scramble the eggs

Step 4

Keep heating the mixture, whisking constantly until it begins to boil. Boil for one minute or until you see thick bubbles bursting on the surface. Remove from the heat

Step 5

Pass the pastry cream through a sieve into a bowl to make sure there are no lumps and set aside to cool

Step 6

Once the custard is cool, chop the chocolate into small pieces and melt the chocolate in the microwave in 30-second increments until completely melted. Set aside to cool while you prepare the butter

Step 7

Beat butter and icing sugar together until pale and creamy

Step 8

Add in cocoa powder and beat until totally incorporated. Scrape down bowl to make sure everything is mixed evenly

Step 9

Switch to a whisk attachment and gradually add the custard, whisking everything together

Step 10

Once the custard is completely added, pour in the cooled melted chocolate and continue whisking until everything is totally combined. The frosting should be smooth, silky and chocolatey