1. Pre-heat oven to 220 degrees C. Grease a baking sheet.
2. Roll out pastry on a baking sheet, prick with a fork. Sprinkle with icing sugar and bake for 15 minutes. Allow to cool completely.
3. Place one part of pastry on a serving plate, spread with half of the custard, top with half of the whipped cream and half of the strawberries. Cover with another pastry and spread with remaining custard, whipped cream and strawberries. Place the last layer of pastry on top.
4. Dust millefeuille with sifted icing sugar. Store in a cool place until needed.
To make custard:
1. Split vanilla pod, place it in a saucepan and pour in the milk. Bring to the boil. When milk has reached boiling point, remove from heat and take out vanilla pod.
2. In a bowl, beat egg yolk with castor sugar until white. Add cornflour, fold in lightly then gradually mix in boiling vanilla-flavoured milk, whisking all the time.
3. Pour mixture into a saucepan, add rum. Cook over gentle heat for 1 minute, stirring vigorously. Transfer custard into a bowl and leave to cool.