The cake :

Pre-heat the oven at 170c.
In a pot, add butter, chocolate and milk, melt and let it cool slightly.

In a bowl sift flour, choco powder, baking soda, baking powder and salt.

In a mixing bowl add egg and sugar, whisk until fluffy, high speed for 5 minutes.

Once the egg done, add flour and the chocolate mixture, combine with spatula until everything is combined.

Divide the batter into 3, 18cm pan (300-400gr each), bake for 35-40 minutes.

Chocolate diplomat cream :

To make the pastry cream, In a pan heat the milk til simmering.

In a mixing bowl add yolk, corn starch, sugar and vanilla, whisk until pale.

Once it's pale, add milk little by little while whisking.

Pour the mix back into the pan on medium low, keep whisking until thicken, throw the butter and chocolate, whisk again.

Sift to a container and cover with plastic wrap, make sure the wrap touches the pastry cream, let cool in the fridge for 30 minutes

Chocolate ganache :

Pour the chocolate in the small mixing bowl and heat the cream until just simmer and pour it over the chocolate, let it sit for 3 minutes.

After 3 minutes, combine the chocolate until it corporate and shiny, then put it in the fridge for 15 minutes or until it's spreadable.

Assembly :

To assembly, slice each cake into two pieces and put a little bit of the cream filling on the board to lock the cake in place.