Preheat the oven to 180`c and line 2 baking trays with non-stick paper. Beat the egg whites until satiny peaks form, and then beat in the sugar a spoonful at a time until the meringue is stiff and shiny. Sprinkle over the cocoa and vinegar, and the chopped chocolate. Then gently fold everything until the cocoa is thoroughly mixed in. Spread onto the 2 baking sheets in into 2 circles 9 inches in diameter, smoothing the top. Place in the oven, then immediately turn the temperature down to 150°c and cook for about an hour. When it’s ready it should feel crispy to touch on the outsides but still soft on the inside. Turn off the oven, open the oven door and allow the meringue to cool down in the oven. Meanwhile, prepare the cranberry jam. Place the cranberries, sugar, orange juice and zest. Bring to the boil and cook down for 15 minutes until the cranberries pop and the jam thickens, adding in a little water if the jam to get too dry. Add in the corn flour, bring to the boil and take off the heat. Allow to cool down completely. When you are ready, place 1 of the chocolate meringues on a serving cake stand. Spread the cooled cranberry jam on top. Next, whip the fresh cream with the icing sugar and spread half over the cranberry jam. Place the second meringue on top and cover with the remaining whipped cream. Decoratively arrange the berries on top and serve dusted with a little icing sugar.