Mix the mint leaves with half of the sugar and chop as finely as possible.
Set a bowl over a pan of simmering water and melt 2 oz. of the chocolate. Remove from heat. Add the egg yolks and whisk until creamy. Leave to cool.
Whip the cream until soft peaks form, then fold in the chopped mint. Fold the whipped mint cream into the cooled chocolate mixture. Freeze the mixture in a 2 quart ice cube tray.
When the ice cream becomes crisp at the edges, whisk for 2 minutes. Return to the freezer, then whisk the ice cream every 45 minutes until it sets.
Whisk the egg whites until soft peaks form Fold in the remaining sugar, then fold carefully into the frozen ice cream. Finally grate the remaining 1 oz. chocolate and stir into the ice cream. Return the ice cream to the freezer until completely set.
Serve decorated with mint leaves dipped in melted chocolate. ( LEAVE TO SET ON WAX PAPER )