These are buttery, sweet, and have a great texture just like sand -- hence the name. They're even better after the lemon flavor has emerged, so try to wait a few days before eating them. And if you have Meyer lemons -- use 'em! They'll be twice as good. —Food52
Test Kitchen Notes
test comment —The Editors
all purpose flour
(2 sticks) unsalted butter, at room temp.
Stir the flour and baking powder together in a small bowl. Scrape the butter into your mixer and beat until creamy (use the paddle attachment, if you have one). Add the confectioner's sugar and beat for a minute. Then add the regular sugar and beat for a minute more. Flick in the lemon zest and salt and mix just briefly. Drop in the egg yolks one at a time, and again, mix for just a few moments to combine. With the mixer on low, gradually add the flour mixture, and blend just until the dough is formed. Use a spatula to do any last mixing.
Divide the dough between two 1-foot-long sheets of plastic wrap. The dough will be quite soft. Don't worry. Shape it into a rough log, 1 1/2 inches round. Wrap the plastic around the dough and continue shaping and rolling to form a nice round log. Twist the ends and tuck them under the log. Refrigerate for at least 2 hours and up to a few days.
When you're ready to bake the cookies, preheat your oven to 350 degrees F and set a rack in the middle of the oven. Line two baking sheets with parchment paper. Lay a third sheet on the counter and pour out a ridge of sugar, approximately the length of the logs, for dipping them in. Then do just that: lay a log on the ridge of sugar and roll it lightly to press some sugar into its sides. Completely coat the logs with sugar, then slice them into 1/4 inch thick slices. A long thin carving knife works well for this. Lay the slices about 3 inches apart on the baking sheets.
Bake for 12-15 minutes (turning the sheets 180 degrees halfway through) until golden on the edges. Cool on baking racks. Store in cookie tin. It's best if you can hold out a day or two before eating- good luck.