Sift the flour, sugar and salt into a large bowl and, using your fingertips, rub in the butter until the mixture resembles coarse breadcrumbs.
Whisk the egg yolk with the water, reserve a little to glaze the bottom of the blind-baked shell, and cut the rest into the flour mixture with a knife until you have a dough.
Knead very gently until smooth, pat into a disc, wrap in cling-film and chill for 30 minutes.
On a lightly floured work surface, roll out the pastry and use to line a 25cm loose-bottomed tart tin, or 4 Yorkshire pudding pans, letting any excess pastry hang over the sides.
Prick the pastry lightly all over with a fork, line with greaseproof paper, fill with baking beans and place on a baking sheet.
Bake blind for 12 minutes.
Remove the greaseproof paper, brush the bottom of the tart with the egg wash and return to the oven until the pastry is cooked and slightly golden, about another eight minutes.
Now ready to fill and cook, times vary depending on fillings.