Orange Walnut Shortbread Bars with Citrus Glaze

Steps

1. Preheat the oven to 325°F (165°C) and line an 8-inch square pan with parchment, leaving an overhang.
2. Spread the walnuts on a small baking sheet and toast in the oven for 7 to 8 minutes until fragrant; let cool.
3. In a large bowl, rub the lemon zest into the granulated sugar with your fingers until fragrant and damp.
4. Add the butter, salt and vanilla to the lemon-zest granulated sugar and beat until creamy and light, about 2 minutes.
5. In another bowl, whisk the flour and cornstarch together, then mix them into the butter mixture on low just until a soft, crumbly dough forms.
6. Fold in the cooled toasted walnuts.
7. Press the dough evenly into the pan and prick all over with a fork.
8. Bake for 35 to 40 minutes until the edges are golden and the center is pale golden.
9. Cool in the pan for 10 minutes, then lift out by the parchment and cut into 12 bars while still warm.
10. Cool the bars completely on a rack, about 30 minutes.
11. For the glaze, whisk the powdered sugar with the orange juice until smooth and pourable, then drizzle over the cooled bars and let the glaze set for 10 minutes.