Make the pastry by putting flour, butter, egg yolk and cold water into a food processor. Process in pulses until the mix binds.
Line a 23cm diameter flan dish or tin (we buttered and floured ours). Nilsen suggests a tin that is about 2.5 cm in height.
On a floured surface roll the pastry out as thinly as you can.
Ease the pastry into the base of the dish, trimming the edge so it sits slightly above the lip of the dish (to allow for shrinkage). Lightly prick the base with a fork and chill for 10 minutes.
Preheat the oven to 200 C (180 C fan).
Line the pastry with foil and weigh down with baking beads (or any other suitable weight – we used a smaller metal pie tin). Bake for 15 minutes.
Remove the beans and foil and bake for another 4-5 minutes until the pastry is pale golden.
If you notice any small holes or cracks, patch up with leftover pastry trimmings.
While the pastry cooks, prepare the filling.