Glazed Lemon Shortbread Cookies

For the cookies:
Get out your food processor. Grind sugar and lemon zest in processor until sugar looks damp and zest is thoroughly incorporated, about 30 seconds. Add the flour, baking powder and salt, then pulse to combine. Scatter in the butter cubes, and pulse until the mixture resembles loose cornmeal.

In a measuring cup or small bowl, beat the yolk, lemon juice and vanilla together to combine. With the machine running, add the juice mixture to the creamed mixture in a slow stream. Process until mixture begins to form a ball, about 15 seconds longer.

Turn the dough out onto a smooth surface, kneading to work any stray dry bits into the dough until smooth. Form into a log about 2 inches in diameter and wrap in wax paper.

Chill until firm and cold, about 45 minutes, or up to a few days. Dough can also be frozen at this point. If frozen, allow to thaw just until cool before proceeding.

Heat oven to 375F. Slice dough into 3/8 inch rounds, and bake on Silpat or parchment covered baking sheets just until edges are golden brown, about 12-14 minutes. Cool on baking rack.

You can store cookies in an airtight container at this point for several days. I don’t recommend glazing them until just before serving. They are also delicious plain, if you are not a glaze kind of person. I am.

Make glaze by whisking all ingredients in a medium bowl until completely smooth. When cookies have cooled completely, dab a bit of glaze onto each cookie, and spread with a knife or the back of your spoon just to the edges.

To make lemon sugar, combine and grind together with a fork the sugar crystals and lemon zest, then sprinkle on top of glazed cookies while glaze is still wet.