200 gmbutter puff pastry1egg, lightly beaten with 1 tbsp milk250 ml (1 cup) Champagne2 pieceslemon rind, removed with a peeler1golden shallot, finely chopped4small green prawns25 mlextra-virgin olive oil1 tbsplemon juiceTo garnish:finely chopped chives
Preheat oven to 200C. Roll out puff pastry on a lightly floured surface to 4mm thick, transfer to a baking paper-lined tray and refrigerate for 30 minutes. Cut out four 6cm-diameter rounds, then using a 5cm-diameter pastry cutter, press 2/3 of the way through each round, leaving a 5mm border. Refrigerate for another 30 minutes. Brush rounds with eggwash then bake for 7-10 minutes. Remove from oven and using a small, sharp knife, detach centre piece of pastry, leaving base intact, and discard. Bake for another 2-3 minutes or until golden and pastry is cooked through. Transfer to a wire rack to cool completely.
Combine Champagne, lemon rind, shallot, prawns and ½ cup water in a small saucepan, bring to the boil, remove from heat and stand for 10 minutes. Using a slotted spoon, remove prawns from liquid, peel, remove intestinal tracts and tails, cut prawns in half widthways and set aside.
Strain poaching liquid, return to medium heat and simmer for 10 minutes or until reduced to 1 tbsp. Strain through a fine sieve and cool completely. Whisk in olive oil and lemon juice and season to taste with sea salt and freshly ground black pepper.
Toss prawns in dressing, divide among pastry cases and serve scattered with chives.