Mix the flour and salt in a large freezer-safe mixing bowl and add the chilled butter. Cover the bowl with a plastic film and keep it in the freezer for 10-15 minutes so the butter won't melt in the next step.
Remove the bowl from the freezer. Using a pastry cutter a pastry scraper, cut the butter into the flour.
Give the dough a quarter turn, and make the same steps at least 3 more times- up to 6 times.
Wrap the dough in plastic film and refrigerate at least for 1 hour or freeze for 20-30 minutes before using.