Cream the butter and sugar together until light. Slowly add the egg and then the flour and salt. Lightly work the mixture together until it binds to a dough. Cover and refrigerate for at least 1 hour before use.
To make a tart to serve six, roll out the pastry to about ⅛ in / 0.2 cm thick, and use it to line a greased 9 in / 23 cm tart tin (or to make individual tartlets, line twenty-four 2½ in / 6.5 cm tartlet tins). Prick the pastry all over. Cover with greaseproof paper, and weight it down with a handful of dried or baking beans. Bake in a preheated oven at 200°C / 400°F / Mark 6 for 8–10 minutes. This is called ‘baking blind’. Remove the greaseproof paper and the beans. The pastry case is now ready for you to add one of the fillings given below (or one of your own). When you have filled the tart case, bake in a preheated oven at 180°C / 350°F / Mark 4 for about 30 minutes (15–20 minutes for individual tartlets) until the filling has set and the top is lightly browned.