Knead butter with 1 oz. flour.
Form into a flat square and set it in a cool place.
In the meantime knead a harder silky smooth retes dough of the remaining flour with cold water, the lemon juice (or a little vinegar) and salt.
Let it rest for 20-25 mins., and roll out to oblong shape (not very thin); place butter in middle and fold edges tightly on (take care that the corners should be free of flour and the thickness of the lower layer and of the four corners resting on each other should be equal), and roll out with rolling pin into an oblong, a little over an inch thick.
Now comes the folding, an operation you have to repeat three times.
After each folding leave the dough in a cool place for 20-25 mins.
Fold pastry in the following way.
Fold two ends so that edges meet in the middle and then fold again in the middle like a book, and leave in a cold place.
Use it for the preparation of any kind of sweets where puff pastry is required.