Ensure cold ingredients are used in the making of the pastry. Prepare the butter by ensuring you have ice-cold water on hand.
Add flour, sugar and salt to a food processor and pulse to combine. Add butter. Pulse until small crumbs form then, with the food processor running, stream in the water and process only until a large ball forms. From when you add the butter to when the balls come together it should take only 15 seconds or so.
Using a rubber spatula, scrape out dough and quickly form into a small disc. Wrap tightly in plastic wrap and set in the fridge for 1+ hours.