First, set up a bain-marie, as we are making a swiss style meringue. Then, preheat oven to 130c.
In a metal bowl, combine egg whites and sugar. Place the bowl over your pot of simmering water, stirring constantly with a wooden spoon. Remove from heat when the mix is too hot to touch.
Take off the heat and whisk the mix until firm and it has doubled in volume. You will get the best results with an electric whisk.
Melt the chocolate (best with bain-marie) and fold into the meringue, leave it a bit uneven for a more marbled effect. Use two teaspoons to place small balls of the mix on a tray with baking paper. Bake for 35min.