Take the butter block from the fridge and wrap it in a piece of foil and return it to the freezer for 30 minutes. Butter needs to remain as cold as possible.
Sift the flour and salt into a mixing bowl. Take the butter out of the freezer, hold it in the foil, dip it into the flour, then grate it on a coarse grater placed in the bowl over flour.
Keep dipping the butter down into the flour to make it easier to grate. At the end, you will be left with a lump of grated fat in the middle of the flour – so now take a palette knife and start to cut it into the flour — don’t use your hands — until the mixture is crumbly.
Add enough water to form a dough that leaves the bowl clean, using your hands. Pop the dough into a polytene bag and chill in fridge for 30 minutes.