Steel knife: Chop butter with sugar until butter is size of small peas, using on/off turns. Add yolks, water, vanilla and salt and mix 3 seconds. Add flour and process just until dough begins to gather together; do not form ball. Transfer to large plastic bag. Working through bag, press dough into disc. Refrigerate or freeze dough until firm. (Can be prepared ahead and refrigerated 3 days or frozen 4 months. Thaw frozen dough in refrigerator until just firm.) Roll dough out between 2 sheets of floured plastic wrap to 1/8-inch-thick round. Transfer to 9-inch-diameter, 1-inch deep tart pan with removable sides. Press dough into pan. Trim off excess dough, leaving 1/4-inch overhang. Crimp to form decorative edge. Refrigerate or freeze dough until firm. Position rack in center of oven and preheat to 400°F. Pierce bottom and sides of dough with fork. Line dough with heavy-duty foil and fill with dried beans, rice or pie weights. Bake 10 minutes. Remove foil and weights. Pierce pastry with fork. Bake until light brown, covering edges with foil if browning too quickly, about 10 minutes. Let cool at least 30 minutes. dess 35