First, make your pastry dough, wrap it in plastic wrap and rest it in the fridge for at least half an hour. Dust a clean work surface with flour, get the pastry out and roll it with a floured rolling pin into a rectangular shape about 1/4 inch thick and big enough to line a shallow, 11x15" baking pan.
Grease the pan with butter and line it with the pastry. Trim any excess off the edges of the pan, leaving a half-inch overhang. Pinch this overhanging dough up to give a little rim. This not only gives it a rustic edge but also stops the pastry from shrinking and it means there’s no need to fill the pastry case with beans or rice before baking it blind. Prick the pastry all over with a fork and chill in the freezer for another 30 minutes.