Sieve flour and salt and mix to a springy dough with water — 1 cup, from which 1 tblspn, is replaced with lemon juice.
Roll out on a floured board and leave for 15 minutes.
Squeeze the butter in a floured cloth, or beat it on a slab with a butter pat to get out most of the moisture, and flatten it to about 1" thickness.
Put the butter in one piece in the middle of the pastry, then fold the pastry up over it, first at the two ends, then at the sides, pressing the edges with a rolling pin to seal in the air.
Leave for 15 minutes or more, then roll into a long, narrow strip.
Fold in four again and leave for another 15 minutes.
Repeat four times, allowing the pastry to rest, covered with a cloth, for 15 minutes between each turn.
Finally roll into required shape.
If time permits, this is much improved if an hour is left between rolling times.
Remem- ber - the pastry must never be allowed to get warm.