Orange-Rosemary Icebox Cookies

Grated zest of 1 orange

2/3 c. granulated sugar

1/4 c. confectioners' sugar

1 T. finely chopped fresh rosemary

1/2 t. kosher salt

2 sticks unsalted butter, at room temperature

1 large egg, separated, plus 1 egg yolk

2 c. all-purpose flour

2 T. sanding sugar

Combine the orange zest, granulated sugar, confectioners' sugar, rosemary, and salt in a food processor and process, scraping the bowl occasionally, until the mixture is sandy and turns orange, about 1 minute. Add the butter and process until creamy, 1-2 minutes. Add the egg yolks and process, scraping the bowl occasionally, until combined, about 1 minute. Add the flour and process until smooth, about 1 minute. (Dough will be very soft.)

Divide the dough in half and place each half on a sheet of plastic wrap; shape each into a 10"-long log. Wrap the 2 logs tightly and refrigerate until firm but not hard, about 1 hour. Unwrap and reshape each into a smooth, even cylinder. Wrap again tightly and refrigerate until very hard, at least 2 hours or overnight.

Position racks in the upper and lower thirds of the oven; preheat to 350 degrees. Line 2 baking sheets with parchment paper. 

Lightly beat the egg white in a small bowl. Brush 1 log all over with some of the egg white, then sprinkle with 1 T. sanding sugar. Using a sharp knife, slice the log into 1/4 to 1/2" rounds. Arrange the slices 2" apart on one of the prepared pans. Repeat with the second log of dough.

Bake, switching the pans halfway through, until the cookies are golden around the edges, 20-24 minutes. Transfer the pans to racks and let cool 5 minutes; then remove the cookies to the racks to cool completely.

Makes about 36 cookies.

Adapted from Holiday Cookie Cookbook, p. 47.