1.Cut pastry sheet in half; stand on a board for 5 minutes or until partially thawed. Liberally grease a 12-hole, deep patty pan with a pastry brush dipped in the melted butter. Cut 12 x 10cm squares of baking paper.
2.Sprinkle half of pastry with caster sugar, top with remaining pastry half. Roll pastry stack up tightly from the short side. Refrigerate until firm.
3.Cut pastry log into 12 x 1cm-wide pieces. Place one pastry piece, spiral-side down, on board dusted with sifted icing sugar mixture; refrigerate remaining pastry. Roll out pastry piece into a 10cm round. Cut a round from the pastry using a 9cm cutter. Press the round into a patty pan hole. Repeat with the remaining pastry pieces. Freeze for 10 minutes.
4.Preheat oven to hot (220°C/200°C fan-forced).
5.Place baking paper squares over pastry in pan; place about a tablespoon of dried rice or beans over paper. Bake 10 minutes in hot oven; remove paper and rice. Reduce temperature to moderately slow (160°C/140°C fan-forced), bake further 10 minutes in moderately slow oven or until base of pastry is browned lightly and crisp. Cool.
6.Reduce oven temperature to slow (140°C/120°C fan-forced).
7.Meanwhile, beat egg yolk and 2 tablespoons of extra sugar in small bowl with electric mixer until thick and creamy; fold in extra butter, milk, rind and juice, then sifted flour.
8.Beat egg white in small, clean bowl with electric mixer until soft peaks form. Gradually add remaining extra sugar; beat until sugar dissolved. Fold into lemon mixture in two batches; divide among pastry cases.
9.Bake in slow oven about 10 minutes or until just set. Remove tartlets from pan; cool on wire rack.
10.Serve tartlets dusted with sifted icing sugar, if desired.
This recipe is best made on the day of serving.Note