To make the seeded pastry, place the flour, sesame seeds, black onion seeds and parsley in a food processor, saving some seeds and herbs for rolling. Add the butter or margarine with ½ tsp of salt. Pulse the blade until mixture resembles fresh bread crumbs. Add water and pulse to form a coherent pastry. Do not over mix. Turn pastry out onto a floured surface, shape into a neat round and refrigerate for 30 minutes.