Whisk 2 1/2 cups flour and salt together in a bowl. Cut in shortening with 2 knives or pastry blender until the mixture resembles coarse crumbs. Add ice water, 1 tablespoon at a time, tossing with a fork, until flour mixture is moistened and dough comes together. Do not add more water than you need. Divide the dough in half and shape into 2 balls. Wrap in plastic wrap and refrigerate, at least 30 minutes.