Divide the dough into equal parts and gently roll them 8 balls. Put them on a tray lined with baking paper. Remember to keep them 5 to 7 cm (2 to 3 inches) apart as they will rise some more. Cover them loosely with some cling wrap lightly coated in oil and let the buns rise in a warm place for at least one hour. Beat the remaining egg with one tablespoon of water and use it to brush the top of buns. Sprinkle them with sesame seeds.