1. Freeze the chocolate for 30 minutes. Meanwhile, preheat the oven to 140°C, then line 2 large baking trays with baking paper.
2. Put a frying pan over a medium heat, add the hazelnuts and dry-fry for a few minutes, stirring, until lightly toasted. Cool, then pop into a food bag and bash with a rolling pin until finely ground or use a grinder, Set aside.
3. Finely grate 50g frozen chocolate into a bowl and put back in the freezer until ready to use. Break the rest into another bowl and reserve.
4. In a large, grease-free bowl, whisk the egg whites and cream of tartar until stiff enough to hold a firm shape. Whisk in the caster sugar 1 tablespoon at a time, until you have a very thick, glossy meringue. Sift in the icing sugar in 3 batches, folding in with a metal spoon each time – the mixture will get very stiff.
5. Mix the cocoa, ground hazelnuts and grated chocolate together. Gradually fold gently into the meringue mixture, which will remain very stiff. Spoon into the piping bag and pipe spiral peaks onto the baking trays, spaced apart, to make 24 small meringues. Bake for 40 minutes (if bubbles start to appear, reduce the oven temperature to 120° or until the bases are firm. Remove from the oven and gently loosen from the paper. Leave to cool on the paper.
Melt the reserved chocolate in a bowl resting over a pan of simmering water – make sure the bowl doesn’t touch the water. Using a knife, smear some chocolate onto the base of each meringue and leave to set in a cool place, chocolate-side up.
7. Whip the double cream to soft peaks. Spoon the whipped cream onto 12 meringue bases and sandwich each one together with a cream-free meringue
8. or you an enjoy a lighter version without using double cream, you an enjoy those tasty mini bites on thier own