Place flour, salt, and sugar in a food processor; cycle to join. Add margarine and interaction until combination looks like coarse feast, around 10 seconds. Add 1/2 to 3/4 cup ice water in a sluggish, constant flow through the feed tube with the machine running, just until the mixture keeps intact. Try not to process for over 30 seconds. Test mixture just barely together; on the off chance that it is as yet brittle, add a smidgen more water.
Turn batter out onto a piece of saran wrap. Press into a smoothed circle and envelop by the plastic. Refrigerate for something like 1 hour prior to utilizing.