Scrape the dough out of the bowl and form into a ball shape.
Cut a cross halfway down the ball and open the dough into a square by pulling out the corners. Neated up the edges if needed and place any cut pieces on top.
Put the dough on the worktop tilted into a diamond shape and gently flatten.
Put the cold butter in the middle and wrap the dough around it as if making a parcel, making sure the seems overlap.
Pull the parcel to the edge of the surface, long length to the edge, and use the rolling pin to start to flatten the butter further.
Turn the dough so that the short length is at the bottom and firmly roll out until the length of the rolling pin is reached. Turn the dough over to make sure it isn't sticking.
Fold the length of dough into 3.
Wrap in a plastic bag and refrigerate for 20-30 minutes
Unwrap the dough and place on the worktop with the open ends top and bottom and repeat the rolling, folding, wrapping, refrigerating process a further 2 times.
Roll out the dough to A4 size, with the long length at the bottom and cut into 4 equal strips.
Cut each strip along the diagonal and gently stretch the dough.
Make a cut at the short end and use the corners to start rolling up the dough into the croissant shape, making sure that the end piece is secured underneath before placing on silicone paper on a baking sheet.
Proof the dough by placing in the oven, raise the temperature to 50C then turn off. Wait 30 minutes.
Glaze the croissants with beaten egg mixed with water.
Preheat the oven to 250C and add the croissants. Turn down the oven immediately to 210C and bake for 10-15 minutes.