Cut/Process the 20g of butter into the flour, sugar and salt.
Add the water until it comes to a dough. Store in the refrigerator for 20 minutes or until dough is cooled through.
Wrap the laminating butter into the dough. Rest dough for 15 minutes in the fridge.
Using a standard cutting board as a guide, roll the dough into a rectangle, following the dimension of the cutting board.
Fold the dough using a book fold, and then half it.
Freeze it for another 15 to 30 minutes, or when butter is solid.
Roll another time and fold the same, book fold and then half.
You now have 64 layers, you can either choose to fold another time, making it 256 layers or use the puff pastry as it is.