Process flour, custard powder, sugar and butter until crumbly. (Or sift the dry ingredients into a bowl, rub in butter.) Add egg yolks and enough water to make ingredients cling together. Knead dough on floured surface until smooth. Divide pastry into four, cover each with plastic; refrigerate for 30 minutes.
Preheat the oven to moderately hot (200°C/180°C fan-forced). Grease 4 x 12 hole (2 tablespoon/40ml capacity) patty pan trays.
Roll out each piece of pastry between sheets of baking paper until 3mm thick. Cut out 48 x 7.5cm rounds, reserving all pastry scraps. Place rounds into prepared trays, fill pastry cases with 1 tablespoon of basic fruit mixture.
Roll pastry scraps between sheets of baking paper until 3mm thick; cut out 16 stars or Christmas trees, place on 16 tarts. Knead pastry scraps into a ball and freeze until firm; coarsely grate onto 16 tarts. Remove a little egg white to a separate bowl; use this to brush on pastry tops; sprinkle with 2 tablespoons white sugar. Cover the remaining tarts (without pastry tops) loosely with foil.
Bake all tarts in a moderately hot oven for about 20 minutes or until pastry is browned. Remove pastry-topped tarts from pan.
Beat remainder of egg whites in small bowl with electric mixer until soft peaks form, gradually add the extra caster sugar, beat until dissolved. Spoon meringue onto remaining untopped tarts; bake in a moderately hot oven for about 3 or 4 minutes or until browned lightly.
Pastry topped pies suitable to freeze. Not suitable to microwave.
Photography by Brett Stevens.