Lemon-Glazed Shortbread Cookies

Steps

1. Measure out 60 g of the powdered sugar for the dough and set the remaining 80 g aside for the glaze. Set aside 2 g of the lemon zest for the glaze; the remaining 8 g goes in the dough.
2. In a bowl, beat the butter with the 60 g of powdered sugar, the 8 g of lemon zest, the salt and the vanilla until light and creamy, about 2 minutes.
3. Whisk the flour and cornstarch together, then mix them into the butter mixture on low just until a soft dough forms.
4. Shape the dough into a log about 2 inches (5 cm) across, wrap it, and chill for 30 minutes until firm.
5. While the dough chills, preheat the oven to 325°F (165°C) and line a baking sheet with parchment.
6. Slice the log into 12 rounds, set them on the baking sheet, and prick each top twice with a fork.
7. Bake 18 to 22 minutes, until the edges are lightly golden. Cool on the sheet 5 minutes, then move to a rack and cool completely, about 30 minutes.
8. For the glaze, stir the reserved 80 g of powdered sugar with the lemon juice and the reserved 2 g of lemon zest until smooth and thick.
9. Spoon the lemon glaze over the cooled cookies and let it set for 15 minutes before serving.