Measure 1/2 cup (120ml) of water in a cup. Add ice. Stir it around. From that, measure 1/2 cup (120ml) of water– since the ice has melted a bit. Drizzle the cold water in, 1 Tablespoon (15ml) at a time, and stir with a rubber spatula or wooden spoon after every Tablespoon (15ml) added. Do not add any more water than you need to. Stop adding water when the dough begins to form large clumps. I always use about 1/2 cup (120ml) of water and a little more in dry winter months (up to 3/4 cup).