For Shortbread

1. Preheat the oven to 150°C (300Fº).
2. Add sugar and lemon zest to the Stand Mixer bowl fitted with Flat Beater Accessory. Turn to speed 2 to infuse sugar with lemon oils for 1 minute.
3. Add butter to sugar and cream together on speed 4 for 2-3 minutes. Turn down to speed 2 and add egg yolk and yuzu juice and mix for an additional 30 seconds.
4. Turn mixer to speed 1 and add flour, powdered sugar, cornstarch and salt. Mix until just combined, about 1 minute.
5. Scrape dough onto a parchment-lined baking sheet and pat into rectangular shape 1 cm (½-inch) thick. Bake for 30-35 minutes or until the edges are lightly golden brown.
6. Let cool for 5 minutes then use a bench scraper to cut into rectangles.

For Glaze

1. To make glaze, in a clean Stand Mixer bowl fitted with Whisk Accessory, add powdered sugar and 1 Tbsp yuzu juice. Turn to speed 1 and mix until smooth. Scrape sides of bowl if needed and add additional yuzu juice 1 tsp at a time if thinner texture is desired.
2. Drizzle glaze over cooled shortbread cookies, sprinkle with lemon zest to garnish.