Soleils (Parisian Butter Cookies)

Directions

1. In a small bowl, combine granulated sugar and citrus zest with your fingers, rubbing the zest to release the oil. This will ensure that the zest is incorporated evenly throughout the cookies.
2. In the bowl of a stand mixer fitted with the paddle attachment, or by hand, cream the butter and sugar together until just combined, scraping down the sides of the bowl to make sure it is evenly mixed. Add the egg and mix until just incorporated, then mix in the vanilla. Add the flour and mix until just combined, scraping down the sides one more time. *Do not overmix!* The dough should still be a bit crumbly, but hold together when pressed.
3. Turn the dough out onto a lightly-floured surface and form it into two disks. Cover tightly in plastic wrap and refrigerate for at least an hour. (At this point, you can leave the dough in the fridge overnight—just be sure to let it sit out at room temperature for 30 minutes or so before rolling so it isn't too chilled.)
4. Preheat the oven to 400°F and cover a few baking sheets with a silpat or parchment paper. Take out one dough disc at a time and roll it out on lightly floured surface until it is 1/4-inch thick. Using a 1 1/2-inch cookie cutter (or the mouth of a glass), cut out cookies. Transfer them to the prepared baking sheets, leaving an inch between them. (Note: If you want very clean-cut cookie shapes, refrigerate cut cookie dough for 30 minutes to an hour before putting in the oven.) Bake for 8 to 10 minutes, or until cookies begin to turn golden brown around the edges. Take out and allow to cool before packing into gift bags, tupperwares, or lunchboxes.
5. Note: These cookies freeze well when stored in a tightly-sealed bag or tupperware container. They're also not too sweet, so would take well to being frosted, covered with sanding sugar (before baking), or being used as the bread to sandwich icing or dulce de leche.