Makes about 24 cookies

Ingredients

• 1 ¼ cups all-purpose flour
• 4 tbsp cornstarch
• 3/4 tsp salt
• 3/4 cup unsalted butter, softened
• 3/4 cup icing sugar
• 1 tbsp milk
• 1 tsp vanilla

Directions

• Preheat your oven to 325F and line 2 baking sheets with parchment.
• Whisk the flour, cornstarch and salt together in a bowl. In the bowl of a stand mixer (or with a handheld blender), beat the butter and sugar together on medium-high until very fluffy and aerated, 4 to 5 minutes, scraping sides and bottom of bowl often. Add milk and vanilla and beat for 1 minute. Sift in half of the flour mixture, then fold in with a spatula until just combined. Repeat with the remaining flour mixture.
• Spoon half of the shortbread batter into a piping bag fitted with a large, open star tip. Pipe the batter into 1 1/2-inch-wide rosettes, 1 inch apart on a prepared sheet.
• Bake the cookies until the edges are lightly browned, 13-14 minutes. Let cool for 3 minutes, then transfer to a rack to cool. Repeat with remaining batter.