Put zest, juices, mint, wine and Cointreau in a bowl (non reactive) overnight in the fridge for flavours to blend. The next day, strain some of the fruit juice into a pan, add the sugar and stir over a low heat until the sugar has dissolved. Chill and then add the rest of the strained juices pouring into a wide chilled bowl. Using a balloon whisk (and not a mixer) whisk the cream until thickened and then whisk into the chilled juices until the mixture thickens to a soft peak consistency. Pour into pretty glasses, champagne flues look nice, and top with the candied zest and mint sprigs.Serve with crisp light biscuits. Pistachio and Hazelnut Crisps: Preheat the oven to 165c/gas 4. Grease and line 3 small loaf tins or 3 small long terrine tins. Since the basic biscuit loaves freeze extremely well, its not worth making a small amount of this mixture. Beat egg whites until stiff and make a meringue with the caster sugar to form stiff peaks. Add in alternately, the flour and nuts very lightly until it is all incorporated. Fill the prepared tins and bake 30-35 minutes until risen, light gold and firm. When cold remove from tins and leave on a cooling tray for at least a day to dry out. Using a sharp knife, slice very thinly into biscuits. Lay in a single layer on baking sheets and dry out completely in a very slow oven for 3/4-1 hour (120c/gas 1/2). Store in an airtight tin. If the biscuits soften, it is a simple matter to dry them out again in a cool oven. Serve with the syllabub.