1 to 3Oranges or clementinesUsing 1 large orange or 2-3 smaller clementines will yield mildly orange results; use whatever citrus you'd like here
2 Sticks(226 grams)ButterAt room temperature. If using salted, reduce salt in recipe to 1/4 tsp
1/3 cup(40 grams)Powdered SugarSifted
1/2 tspFine Sea Salt
1 Egg Yolk
2tspVanilla Extract or Dark Rum
2 cups(272 grams)All Purpose Flour
1/2 cup(2 oz)Pistachios, chopped fineRoasted, lightly salted pistachios work great here; or, you may toast your own prior to chopping. Some larger chunks are fine, but keep in mind you'll need to be able to cut through the cookies with ease
1/2 cup(2 oz)Chopped dark chocolateI used 70%, but any dark chocolate bar would work; it works best to use chopped high-quality chocolate for best flavor and melting. See note about chunk size with the pistachios
Place granulated sugar in a large bowl - of a stand mixer if you have one - and zest the orange/clementines on top. Work the zest into the sugar until moist and fragrant.
Add the butter, sifted powdered sugar and sea salt to the bowl, and using the paddle attachment of the mixer (or, a wooden spoon or spatular or hand mixer), lightly cream the butter and sugar on low speed until combined. The goal is not to whip air into the mixture like American style cookies.
Stop mixing, and scrape down the bowl thoroughly. Add the egg yolk and vanilla extract/rum (if using), and mix again on low until incorporated, taking care to not whip in air into the mixture. Scrape down bowl to ensure even mixing.
Add the flour, and mix briefly (about 2-3 turns of the paddle). Add the pistachios and chocolate, and mix briefly just to combine. Finish mixing by hand, using a spatula or wooden spoon, taking care to incorporate everything just until it is homogenous. It is key to not over work the mixture once the flour has been added.
Scoop out the dough onto 1 large piece of parchment or plastic wrap. Cut off the piece of parchment or plastic wrap and prepare another. Divide dough in half (eye-ball it), and place the other half on the other piece of parchment or plastic wrap.
Form into logs that are 9" long, using the parchment or plastic wrap in place of flouring the counter. You may also roll on a very lightly floured counter. It's sometimes helpful to place the dough into a large piece of parchment, folding the parchment over the dough mass, and use a ruler or bench scraper to push the dough into a log.
Allow the logs to chill for at least 3 hours, or freeze for up to 2 months (tightly wrap and place in bags).
To bake, preheat oven to 350F. Place 1 rack in the middle of the oven, or, if you'd like to bake more than one at a time, at even spaces in the oven. Line baking sheets with parchment or silpat.
Prepare egg yolk wash by whisking 1 egg yolk with 1 tsp water. Sprinkle demerara or other coarse sugar on a piece of parchment or other flat surface. Brush egg wash onto the cookie log, and roll in the sugar, pressing gently to get the sugar to stick.
Cut cookies into 1/2" discs using a sharp, sturdy, non-serrated knife. Place about 2" apart on the lined cookie sheets. These spread slightly while baking.
Bake for 18-22 minutes, until just turning golden. Allow to cool for a moment before transferring onto cooling racks, and then allow to cool thoroughly. These cookies have the best flavor and texture once they have cooled.
Store in a container at room temperature for a few days - they keep well! Or, freezer in a sealed container for a few weeks.
You may use whatever type of mix-in's you'd like in place of the orange zest, pistachios and chocolate. Flavor with a vanilla bean, or any type of extract you desire.