Updated Nov 13, 2019Chatelaine
- PREHEAT oven to 325F. Line 2 baking sheets with parchment.
- WHISK flour, cornstarch and salt in a bowl.
- BEAT butter and sugar in a large bowl using an electric mixer on medium-high until very fluffy and aerated, 4 to 5 min, scraping sides and bottom of bowl. Add milk and vanilla and beat for 1 min.
- SIFT in half of the flour mixture, then fold in with a spatula until just combined. Repeat. Spoon half of the shortbread batter into a piping bag fitted with a large, open star tip.
- PIPE batter into 1 1/2-in.-wide rosettes, 1 in. apart, on a prepared sheet.
- BAKE shortbread until edges are lightly browned, 15 to 16 min. Let cool for 3 min, then transfer to a rack to cool. Repeat with remaining batter.
A note on butter: For these whipped shortbread cookies, we prefer to leave the butter out overnight (although the warmer your kitchen, the less time it will need to come up to temperature). To ensure your batter becomes soft enough to be easily piped, the butter should be so malleable that it can be dipped into with a spoon.
*Cooler butter will still blend into the dough, but it will make piping the rosettes much more difficult. Should this happen, let the dough sit and warm further before continuing with piping.
Kitchen Tip: Trace 1 1/2-in. circles onto parchment. Flip the parchment paper over and use circles as a guide when piping rosettes.