First make the pastry. In a food processor, electric mixer or by hand, beat the butter and sugar together until smooth and creamy. Slowly mix in the beaten egg (scraping the sides of the bowl every so often if you are using a mixer), then gradually fold in the flour to form a smooth dough. Shape into a ball, wrap in cling film and refrigerate for 30 minutes.
Lightly grease a 25 x 4cm de