Pink Grapefruit Shortbread

Directions

1. 1
   Position racks in the upper and lower thirds of the oven and preheat to 350 degrees F. Beat the butter, egg yolk, 2 tablespoons grapefruit zest and the salt in a large bowl with a mixer on medium speed until light and creamy, about 3 minutes.
2. 2
   Add 1 cup confectioners' sugar and beat until combined.
3. 3
   Reduce the mixer speed to medium low and gradually beat in the flour until incorporated.
4. 4
   Turn the dough out onto a lightly floured surface and dust with flour.
5. 5
   Gently knead a few times until soft but not sticky, dusting the surface with more flour as needed.
6. 6
   Roll out to slightly thicker than 1/4 inch thick and cut out circles with a 2-to-2 1/2-inch-round cookie cutter.
7. 7
   Gather the scraps and reroll to cut out more cookies.
8. 8
   Arrange the cookies 2 inches apart on 2 baking sheets.
9. 9
   Bake, switching the pans halfway through, until the cookies are firm and golden brown on the bottoms, 15 to 18 minutes.
10. 10
    Let cool 5 minutes on the baking sheets, then transfer to racks to cool completely.
11. 11
    Whisk the remaining 1 cup confectioners' sugar, 1 tablespoon grapefruit juice and the remaining 1/2 teaspoon zest in a bowl until smooth.
12. 12
    Gradually whisk in up to 1 tablespoon more grapefruit juice until the glaze is spreadable.
13. 13
    Tint pink with food coloring.
14. 14
    Spread about 1/2 teaspoon glaze on each cookie.
15. 15
    Sprinkle with coarse sugar.
16. 16
    Photograph by Levi Brown