Wash & dry the fruits, keep 6 of each back for decoration, and gently mash the rest together with a fork and the icing sugar for a touch of sweetness.
Place a dollop of fruit in the bottom of each of the dishes
Melt the chocolate very gently in a bowl sitting over a pan of barely simmering water, don’t let the bowl touch the water.
Immediately the chocolate has melted, take the bowl off the pan, add the butter and stir in to melt. Then add the egg yolks and finally the balsamic vinegar.
In a separate clean bowl, whisk the egg whites to soft peaks, add the caster sugar and whisk again.
Gently fold the egg whites into the chocolate mixture. A light touch is what is needed here as if you beat this too much you will lose the air in the whisked egg whites. Ensure you pick up all the chocolate mixture at the bottom of the bowl though as you fold the two mixtures together.
Carefully put the mousse into each cup with a small spoon (to ensure you don’t drop any around the sides of the dishes), on top of the fruits.
Put the mousses in the fridge to set until required.
Take the mousses out of the fridge and allow to return to room temperature before serving, decorated with the reserved fruit on top (or to the side if you prefer) and a light dusting of sieved icing sugar on top of each mousse.