the great unshrinkable sweet tart shell

INGREDIENTS

• 1 1/2 cups all-purpose flour
• 1/2 cup confectioner’s sugar
• 1/4 teaspoon salt
• 1 stick plus 1 tablespoon (9 tablespoons; 4 1/2 ounces) very cold (or frozen) unsalted butter, cut into small pieces
• 1 large egg*