adapted from a recipe in Bon Appetit
• 2 cups all-purpose unbleached flour
• 3/4 cup powdered sugar
• 1/4 cup cornstarch
• 1/4 teaspoon salt
• 1 cup (2 sticks) unsalted European-style butter, room temperature
• 1/4 cup granulated sugar
• 1 teaspoons vanilla extract
1. Sift flour, 3/4 cup powdered sugar, cornstarch, and salt into medium bowl. Using electric mixer, beat butter in large bowl until fluffy. Gradually beat in granulated sugar and vanilla. Stir in dry ingredients in 3 additions, mixing until just blended each time. Gather dough into ball; divide in half. Roll each half into a 6-inch-long log; wrap each log in plastic wrap and refrigerate at least 2 hours or overnight.
2. Position racks in top third and center of the oven. Preheat to 325˚F. Cut each log crosswise into 1/3-inch-thick slices (see NOTE below). Arrange slices on 2 heavy large baking sheets lined with parchment, spacing cookies 1/2-inch apart. Bake cookies 9 minutes. Reverse baking sheets; bake just until cookies turn golden brown at edges, about nine minutes longer. Watch cookies closely at this point. Cool cookies on sheets 1 minutes, then transfer to racks to cool. NOTE: If you decide to roll the cookies in sugar, mix 1 egg white with 1 teaspoon cold water; brush over the entire log before slicing. Fill a small dish with the coarse sugar and rotate the edge of the sliced cookie in the sugar completely coated; place on cookie sheet and proceed the same way with the remaining cookie slices.