Via confessionsoftart.blogspot.com
recipe from Leonor at Flagrante Deliciamakes 12 [I got about 16]:
50 g powdered sugar
125 g butter, room temperature
1 g salt
Zest of 1/4 lemon [I used orange]
20 g egg white
150 g wheat flour [or all purpose flour]
Powdered sugar to sprinkle
Cream the butter and sugar together. Add lemon zest and salt and beat for another minute to incorporate. Add the egg whites and whip for a minute or two, until the egg whites are fully incorporated. Gently mix in the flour.
Fit a pastry bag with a star nozzle and, over a siplat or a lined baking sheet, pipe “W”s or “S”s, about 2 inch height. Refrigerate for at least an hour.
Preheat the oven to 350F and bake for 8-10 minutes, or until cookies are golden around the edges [it took me a little longer, about 15 minutes). Cool and sprinkle with icing sugar. Best served the same day as made, but will keep in an airtight container for at least a few days.