Preheat oven to hot, 200C. Lightly grease each recess of a (¼ cup) muffin pan.
Using a 10cm cutter, cut 12 rounds from pastry. Ease pastry into prepared pans. Chill for 15 minutes. Prick bases and bake for 5-10 mins.
Meanwhile, combine water, lemon juice, sugar and cornflour in a saucepan, until smooth. Bring to boil, stirring constantly, until mixture thickens. Reduce heat and simmer for 3 mins.
Stir in yolks, butter and rind and allow to cool slightly. Spoon into prepared cases, leveling top. Chill until firm.
To make the meringue, in a clean, dry bowl, using an electric mixer, beat egg whites until soft peaks form. Gradually add sugar, one tablespoon at a time, beating until sugar dissolves and foam is stiff, thick and glossy. Beat in vinegar.
Increase oven to very hot (220C). Dollop meringue roughly over filling in each tart. Bake for 4-5 mins until lightly browned. Allow to cool and store in an airtight container.
