.
Repeat the folding, turning and rolling process, as before, three more times (do not roll out the pastry the final time you fold and turn it). Wrap the pastry in cling film and chill in the fridge overnight.
When the pastry has rested, roll it out to a thickness of 0.5cm/¼in. Cut the pastry into two 50x20cm/20x8in strips, then cut each strip into triangles about 10cm/4in wide at the base..
With the narrow point of one of the pastry triangles facing away from you, use your fingertips to stretch the two points of the triangle nearest to you out sideways so that they bow a little.
Roll the pastry over itself, curling it into a traditional crescent shape, so that the furthest point of the triangle ends up curled over the top of the croissant.
Repeat the process with the remaining pastry triangles to create about 20 croissants.
Place the croissants onto baking trays lined with silicone paper or baking parchment. Brush them all over with the beaten egg, then set aside to prove for 30-45 minutes. (NB: The croissants can be frozen at this point, if desired.)
Preheat the oven to 190C/170C Fan/Gas 5. Bake the croissants for 20-25 minutes, or until risen and golden-brown. Serve warm with jam and butter.
Recipe tips
These croissants need to be started the day before you want to serve them. Use very cold, high-quality butter for best results.
