1. In a bowl mix flour with cornstarch and salt. Set aside. In a large bowl mix the butter and confectioners’ sugar on high speed until light and fluffy. Add the lemon zest, lemon juice, and vanilla extract and mix until well combined. Add the flour mix in 3 batches and mix until just combined – do not overmix. Place the dough on a big piece of plastic wrap and form a long roll with a diameter of roughly 1.5 inches (3,5cm) – if it gets too long, cut in half and make two rolls. Wrap in the plastic wrap and place in the fridge for at least 1 hour to get firm.

2. Preheat the oven to 350˚F (175°C). Line two baking sheets with baking parchment and set aside. Take the dough out of the fridge, unwrap, cut into 0.25 inch (0,5cm) thick slices, and place on the baking sheets. Bake for 12-15 minutes – the cookies should be lightly golden, but still kind of soft when you touch them. Take out of the oven and let cool down on the baking sheet for 10 minutes. While the cookies are cooling down a bit, add the confectioners’ sugar to a small bowl. Place one cookie at a time in that bowl and flip to all sides so the cookies are completely covered with the sugar. Place on a wire rack and let cool down completely. Store in an airtight container (up to 1 week).