Make the pastry by placing the flour and butter in a food mixer with the paddle attachment and gently mix until it resembles breadcrumbs.
Add the icing sugar and mix through.
Add the egg yolks, vanilla bean paste and the milk and mix until it begins to form a dough.
Take the dough out of the food mixer and split it in half. Shape each portion into a block about 1cm thick, this will make it easier to roll out. Cover it in clingfilm and rest in the fridge for at least 1 hour.
Next make the custard filling while the pastry is resting, place the egg yolks, flour, milk, caster sugar and vanilla bean paste in a saucepan and whisk to combine.
Stir over a gentle heat with a wooden spoon or spatula for 10 minutes until thickened and it coats the back of the spoon.
Stir the white chocolate into the custard until it has melted and is smooth, put the custard in bowl and set it to one side to cool.
Take a 23cm loose bottomed tart tin and roll out the pastry between two sheets of greaseproof paper so that you don't add any extra flour. When the pastry is rolled out big enough to cover the tin lay the pastry over the tin, pressing it into the sides and base of the tin.
Trim the pastry a little, but leave a bit of excess pastry, pour the cooled custard into the pastry case and spread it out evenly. Place in the fridge to chill as you roll out the pastry top.
Preheat the oven to 180C/ 160C FAN/ gas 4 and roll out the other piece of pastry so that it is big enough to cover the top of the pie, take the pie from the fridge and with a pastry brush, brush egg yolk mixed with a litter water around the exposed edge of the pastry, then lay the rolled out bit of pastry on top and press them together.
Trim the excess from the pie and then using a flower plunger cutter, cut out different sized flowers and put these all over the top of the pie and brush with egg wash, then sprinkle the pine nuts over the pie, or decorate however you like with the excess pastry.
Bake for 45 minutes or until golden, leave in the tin to cool so that the pastry and custard continue to cook more. Then remove from the tin and place on a rack to cool.
Can be served warm or cold.