Preheat the oven to 140C/275F/Gas 1.
Line two baking trays with greaseproof paper.
In a clean, dry bowl whisk egg whites until soft peaks form.
Gradually whisk in the sugar until stiff peaks form.
Stir together the chocolate and cocoa and fold gently into the meringue.
Spoon tablespoons of the mixture onto the prepared trays and quickly put in the oven before the mixture loses volume.
Cook for 40 minutes.
To make the cream, gently melt the chocolate with the cream in a small heavy-bottomed saucepan.
Pour into a bowl and allow to cool.
To serve, make a 'sandwich' using two meringues and the chocolate cream as the filling.