1. Place flour and salt in the work bowl of a food processor. Add butter pieces and process with on-off pulses until chunks are size of kidney beans.

2. Combine lemon juice and water. With motor running, pour liquid into work bowl in a steady stream. This should take no longer than 30 seconds; dough shouldn't come together in the bowl.

3. Turn out dough onto a lightly floured work surface and push into a rectangle. Sprinkle lightly with flour and roll out to 1/2 inch thick. Fold into thirds, letter style.

4. Turn so ends are at 6 and 12 o'clock and roll out to a thickness of 1/2 inch. Fold into thirds. Repeat one more time. Wrap dough in plastic; chill at least 4 hours.