Preheat the oven to 180 degrees celcius.
Whisk the egg whites and sugar together until light and fluffy. Fold in the flour and the ground almonds.
Melt the butter in a pan on a low heat. Add the chocolate and mix it in to melt.
Mix the chocolate with the flour mixture.
Spoon into small rectangular silicon moulds on a baking tray and cook in the oven for 15 -20 minutes.
Leave to cool before serving.
«Use a good quality 70% dark chocolate for baking. This gives a lovely rich flavour.»