To make 2x 30cm tart moulds
250g butter
200g icing sugar
a medium pinch of salt
500g flour
4 egg yolks
4 tablespoons cold water/milk
You can make this pastry by hand or in a food processor. Cream together the butter, sugar and salt and then rub or pulse in the flour and egg yolks. When this mixture has come together, looking like coarse breadcrumbs, add the cold milk or water. Pat and gently work together to form a ball of dough. Lightly flour and push, pat and squeeze into shape. The idea is to get your ingredients to a dough form with the minimum amount of movement, i.e. keeping your partry flaky and short (the more you work it, the more elastic it will get, causing it to shrink in the oven and be chewy).
I normally roll the pastry into a really large, short and fast sausage shape, wrap it in cling-film and place in the fridge to rest for at least 1 hour.