Start by drizzling 1/2 cup (120 ml) of the ice-cold water (but not the cubes, if there are any left!) over the butter and flour mixture. Using a rubber or silicon spatula, gather the dough together. You’ll probably need an additional 1/4 cup (60 ml) of cold water to bring it together, but add it a tablespoon as a time. Once you’re pulling large clumps with the spatula, take it out and get your hands in there (see how that big bowl comes in handy?). Gather the disparate damp clumps together into one mound, kneading them gently together.