Lemon Oat Shortbread Cookies

Steps

1. Measure out the powdered sugar and set aside 40 g of it for the glaze; the remaining 60 g goes into the dough.
2. In a large bowl, beat the butter with the 60 g of powdered sugar until pale and fluffy, about 3 minutes.
3. Beat in half of the lemon zest, the vanilla and the salt.
4. Pulse the oats in a blender or food processor a few times until coarsely chopped, then stir the oats and the flour into the butter mixture just until a soft dough forms.
5. Shape the dough into a log about 2 inches (5 cm) across, wrap it and chill for 30 minutes until firm.
6. Preheat the oven to 325°F (165°C) and line a baking sheet with parchment.
7. Slice the chilled log into 12 rounds and set them on the baking sheet about 1 inch (2.5 cm) apart.
8. Bake for 16 to 18 minutes, until the edges are light golden and the centers look set.
9. Cool the cookies on the sheet for 5 minutes, then move them to a rack to cool completely, about 20 minutes.
10. Make the glaze: whisk the reserved 40 g of powdered sugar with the lemon juice and the remaining half of the lemon zest until smooth.
11. Drizzle the glaze over the cooled cookies and let it set for 10 minutes before serving.