In a food processor combine flour and salt. Add butter and pulse until butter is the size of peas. Whisk together the yolk and 1/2 cup cold water. Drizzle the liquid into the food processor while pulsing to combine. Pulse until dough holds together when you pinch it, adding liquid as needed.
Turn dough onto a shet of plastic wrap and from into a ball. Divide in half and wrap each half in plastic wrap, flattening into a disk. Chill until cold or ready to use, about 30 minutes.
On a floured surface roll dough until it's 3/16 inch thick and large enough to fit in the tart pan. (Pinch edges of dough as you roll to prevent cracks and tears.) Place dough into tart pan; gently lift into place without stretching and press into pan. Use the heel of you hand or a rolling pin to trim the edges flush with the pan. If blind baking, freeze crust about 20 minutes.
For blind baking, heat oven to 375 degrees F. Line the chilled crust with aluminum foil, pressing foil into the corners. Fill with pie weights or dried beans and place on a baking sheet. Bake until crust is set and just starting to brown, about 30 minutes. Remove foil lining and weights and return crust to oven to brown evenly, 5 to 10 minutes more. Cool completely, then remove from tart pan. Makes 2 Single Crusts.
CHEESE AND HERB CRUST VARIATION FOR TOMATO TART: Add 1/2 cup grated Gruyere or Jarlsberg cheese and 2 teaspoon chopped fresh oregano or thyme to the food processor with the flour and salt. Proceed with recipe as directed.