1.Combine egg yolks, sugar, rind, juice and butter in small heatproof bowl; stir over small saucepan of simmering water until mixture thickens slightly and coats the back of a spoon. Remove pan from heat, remove bowl from pan immediately; cover surface of lemon curd with plastic wrap; refrigerate until cold.
2.Preheat oven to 200°C/400°F.
3.Meanwhile, make meringue by beating egg white in small bowl with electric mixer until soft peaks form; gradually add sugar, beating until dissolved between additions.
4.Place pastry cases on oven tray; fill with curd, then top with meringue.
5.Bake about 5 minutes or until meringue is browned lightly.