Rosemary Sugar Cookies

Directions

In a stand mixer fitted with the paddle attachment, mix the butter and granulated sugar on medium-low speed until just combined. Scrape down the bowl and paddle, and add the flours, cornstarch, rosemary, and salt. Blend on low speed until just incorporated. Form the dough into three 1/2-inch-thick disks and refrigerate for at least an hour or up to overnight. Position a rack in the center of the oven and heat to 350°F. Line 1 or more large rimmed baking sheets with parchment. Take 1 dough disk out of the refrigerator and let sit at room temperature just until pliable enough to roll, about 5 minutes. Roll between 2 pieces of parchment into a 7-inch round, 1/4 inch thick. Remove the top layer of parchment. Beat the egg with 1 Tbs. water. Brush the round lightly with the egg wash. Using a sharp knife or pizza cutter, cut the round into 8 wedges. Garnish each wedge with a rosemary leaf, if you like, and then sprinkle all over with granulated sugar. Sprinkle a thick coating of coarse-grained sugar on the rounded edge of each cookie. Transfer to the prepared baking sheet, spacing about 1inch apart. Refrigerate for 15 minutes. Bake until light golden brown all over, 13 to 15 minutes. Let cool briefly on the baking sheet, and then transfer to a rack to cool completely. Repeat with the remaining two disks. Store in an airtight container at room temperature for up to 2 days.