Roll the pastry out thinly on a lightly floured surface, then stamp out 24 × 6 cm (2½ inch) circles with a fluted biscuit cutter and press into the buttered sections of 2 × 12-section mini muffin tin. Reknead and reroll the pastry trimmings as needed. Prick the base of each tart 2–3 times with a fork, then chill for 15 minutes.
Line the tarts with small squares of nonstick baking paper and baking beans and bake in a preheated oven, 190°C (375°F), Gas Mark 5, for 5 minutes. Remove the paper and beans and cook for a further 4–5 minutes until the bases are crisp. Remove the cases from the tins and cool on a wire rack.
Pour the cream into a small saucepan, add the sugar and bring just to the boil. Take off the heat, add the chocolate and leave for 5 minutes until melted. Stir until smooth, then gradually mix in the brandy. Leave to cool, then transfer to the refrigerator for about 1 hour until thick enough to pipe.
Spoon the mixture into a piping bag fitted with a star nozzle and pipe whirls of truffle mixture into each tart case. Decorate with chocolate curls, made using a swivel vegetable peeler, dust with a little sifted icing sugar, if liked, and chill until ready to serve.