Mix the flour, salt and sugar together in a large bowl.
Add the butter and toss it in the flour. Use your fingers to squeeze and rub the butter cubes to flatten them. Keep squeezing and rubbing until all the cubes have been flattened. You want a mix of large and small flat pieces of butter.
Make a well in the centre and pour in the water and vinegar. Carefully scoop the dry ingredients from the edges to the centre of the bowl to start bringing the dough together. Using your whole hand, gently squeeze the ingredients together until the dough starts just holding together in a shaggy mess.
Tip the mix onto a clean bench and use both hands to gently squeeze and knead the dough until it mostly holds together. The dough should still be quite shaggy, albeit holding together, and you still want to see streaks of butter in the dough. So be careful not to overwork it.
Use the heel of your palm to flatten the dough into a rectangle 2-3cm thick and, from the short end, roll the dough into a spiral.
Turn the dough 90 degrees and repeat the previous step.
Flatten the dough once again and cut in half. Shape each portion into a flat disc, cover in plastic wrap and chill for an hour, or up to 3 days.
