Add flour and salt, mix lightly til it comes together.
Let the dough rest for 10 minutes in room temperature, covered in clingfilm.
Knead the dough by hand for a couple of minutes.
Cover the dough in clingfilm and let it rest in the fridge over night.
Roll out the dough to a large rectangle. Place butter on one half and fold the other half of dough on top.
Roll again to a long rectangle. Fold in thirds by bringing the bottom up and the top down over it.
Repeat previous step twice.
Chill dough again.
Roll the dough to a long rectangle, about ½ cm thin.
Cut out triangles and roll together to croissant shapes.
Freeze the croissants on a tray.
When frozen place the croissants in plastic bags and keep in the freezer til the day before you want to cook them.
Place croissants on a tray lined with baking parchment. Cling film and keep in the fridge over night. In the morning take the croissants out and let proof in room temperature for about 2 hours.
Bake on 180 degrees for 15-20 minutes or until dark golden brown.
Recipe by at https://www.seasontocook.com/croissants/