Preheat the oven to 170° Celsius with a baking tray on the middle shelf (this is important so that the Soufflés can get a kick start when you put them in the oven, and to make getting them out easier)

use a pastry brush to butter the inside of 4 Soufflé dishes 10cm across x 7cm high

sprinkle the cocoa into the dishes and rotate until the butter is completely coated, shake out the excess

over a bain-marie mix together the pastry cream, Cointreau and zest and keep it warm (I left the stove on 1 and use a bigger bowl than you think you need!)

whisk the egg whites to soft peaks then gradually add the sugar and whisk until firm but not too stiff

whisk a quarter of the egg whites into the base until smooth - do this off the heat!

using a spatula fold in the balance of the egg whites

fill your Soufflé dishes half way, place the truffle in the mix and then fill to the top and smooth off with a palette knife

sprinkle the top with icing sugar and leave to melt for 1 minute (this will give it a lovely crunchy top)

repeat and then thumb the edge

bake for 10 - 12 minutes