1 Sift together the flour and the salt into a mixing bowl.
2 Work the butter with a knife until it is soft. Rub 50 g| 2 oz butter into the flour and salt.
3 Add the water and lemon juice and mix to a farily soft elastic dough.
4 Knead lightly on a floured surface until smooth.
5 Roll out the dough into an oblong, 3 times as long as it is wide.
6 Dice the remaining butter and put 1/4 of it over the top 2/3 of dough. fold the bottom third up and the top third down and give it a half turn, so that the folds are now at the sides. Seal the edges by pressing with a rolling pin.
7 Repeat the rolling and folding process until all the butter is used.
8 Wrap the dough in clingfilm and chill for at least 30 minutes before using.