Place on the preheated baking tray and bake blind for about 15 minutes, or until the pastry is set and pale brown. Line the pastry case with parchment paper and fill with ceramic baking beans or uncooked rice.
Prick the base of the pastry using a fork then chill the pastry for 10 minutes. Roll the pastry out on a floured surface and use it to line a 28cm/11in flan tin. Wrap in cling film and chill for 20 minutes. Process until the mixture just holds together (do not over work as it will make the pastry tough). Add the sugar and mix, then add the egg and a tablespoon of water. To make the pastry, either rub the flour and butter together using your fingertips until it resembles breadcrumbs or measure the flour and butter into a food processor and briefly process until just rubbed in.