In the bowl of a food processor fitted with the blade attachment, pulse together the flour, salt, sugar and butter until the mixture resembles cornmeal with some pea-size pieces of butter remaining.
In a small bowl, stir together the ice water and the lemon juice. Slowly add the liquid to the flour mixture, pulsing, until the dough just comes together. Squeeze a small piece of dough between your thumb and index finger to make sure it holds its shape.
Turn the dough out onto a lightly floured surface and divide it in half. Gently turn over each piece of dough a few times so that any dry bits are incorporated. Form each piece into a loose disk, wrap in plastic, and refrigerate for at least 20 minutes.