In a medium bowl, stir together flour, orange zest, and salt with a fork until combined. Add cold butter, tossing to coat. Using a pastry blender or 2 forks, cut in butter until mixture is crumbly and butter is pea-size. Add ¼ cup (60 grams) ice water, 1 tablespoon (15 grams) at a time, stirring with a fork to bring dough together.

Turn out dough onto a clean surface, and knead by hand until flour is well combined. Shape into a 5-inch disk. Wrap tightly in plastic wrap, and refrigerate for 30 minutes.