Cut the dough into 8 long strips and roll each strip of dough tightly around itself, so that to form a knot.
Place each knot on a prepared tray, making sure the end of the strip is tucked on the bottom.
Cover with a cling film and leave to rise until doubled in size, for about 2 hours.
Preheat the oven to 180°C (355°F) and position the baking rack in the middle of the oven.
Beat the remaining egg in a small bowl, brush the brioche with the beaten egg and bake for 15 minutes (or until it turns golden brown).