To make the pastry place the flour, sugar and butter in the bowl of a food processor and pulse until the mixture resembles fine breadcrumbs. Add the egg yolk and pulse to combine. With the food processor running drizzle in the cold water. Pulse until the mixture comes together. Wrap the pastry in plastic wrap and refrigerate for 1 hour.
Roll out the pastry on a lightly floured bench until 3mm thick and line 6 10cm loose bottomed tart tins and trim the excess. Refrigerate for 1 hour.
Preheat the oven to 180 celsius (350 Fahrenheit) and line each tart with foil and fill with baking weights or beans and bake for 15 minutes. Remove the foil and weights and bake for a further 5 minutes, or until golden. Cool completely.
Place the cream in a saucepan and bring to a boil and remove from the heat. Add the vanilla seeds and bean and leave to infuse for at least 1 hour (or even overnight in the refrigerator).
Heat the oven to 120 celsius (250 Fahrenheit) and remove the vanilla pod and add the egg yolks and sugar and whisk to combine. Strain the mixture through a fine mesh sieve and fill each tart base. Bake for 20 minutes or until just cooked. Dust with nutmeg and set aside to cool.