Dissolve the cornstarch in 2 tbsp of cold milk and keep it aside.

Heat the milk and cream on a low flame for a few minutes, but do not let it simmer.

Melt the chopped chocolate in a double boiler (or in the microwave), when melted keep it aside.

Beat the egg yolks and sugar until pale, add the cornstarch and milk mixture and beat until well incorporated.

Add the warm milk and cream, the melted chocolate and the cocoa powder and keep whisking.

Pour this mixture into a pot and put it on the fire. Cook it on a slow flame, until it thickens. It needs to be quite thick (though it will become thicker when cold). Make sure to constantly stir the cream so it does not burn.

If the cream is not smooth, you can blend it for a few seconds with a hand mixer.

Let it cool down for a few minutes and make sure to stir it often to prevent a film from appearing on the surface.

Transfer the cream into serving glasses and let it cool down completely in the fridge.

Whip the cold cream together with the icing sugar and vanilla extract and pipe it on top of the cold Crème Chocolat.