I've found that a buttery baked good is a delicious vehicle for our boldly flavored trail mix, like in our Mt. Rosemary Scones. This shortbread recipe makes a beautiful and festive cookie, studded with bright green pumpkin seeds and ruby red cranberries. Dark chocolate and pops of candied ginger create a delightful holiday treat.
1 cup plus 2 tablespoons/255 grams total salted butter (2¼ sticks), cold (room temperature if you're using a handheld mixer), cut into ½-inch pieces (see note)
½ cup/100 grams granulated sugar
¼ cup/55 grams light brown sugar
1 teaspoon vanilla extract
2½ cups/325 grams all-purpose flour
6 ounces/170 grams Mt. Rosemary Trail Mix
1 large egg, beaten
Demerara sugar, for rolling
Flaky sea salt, for sprinkling
Line two rimmed baking sheets with parchment paper. Using a stand mixer fitted with the paddle attachment or an electric hand mixer, beat the butter, both sugars and vanilla on medium-high till it’s super light and fluffy (3 to 5 minutes for a stand mixer; 6 to 8 for a hand mixer). Using a spatula, scrape down the sides of the bowl and, with the mixer on low, slowly add the flour, followed by the trail mix, and mix just to blend. If necessary, knead the dough with your hands to make sure the flour is totally incorporated. At this point, the dough should be smooth and feel like Play-Doh with no pockets of flour.
Divide the dough in half, placing each half on a large piece of plastic wrap. Fold the plastic over so that it covers the dough to protect your hands from getting all sticky. Using your hands, form the dough into a log shape; rolling it on the counter will help you smooth it out, but don’t worry about getting it totally perfect. (Don't be afraid to make them compact. Shortbread is supposed to be dense. That's part of why it's so good.) You can also do this using parchment paper, if you prefer, but plastic wrap is easier when it comes to shaping the log. Each half should form a 6-inch log, 2 to 2¼ inches in diameter. Chill until totally firm, about 2 hours.
Heat the oven to 350 degrees. Brush the outside of the logs with the beaten egg and roll them in the demerara sugar (this is for those really delicious, crisp edges).
Using a serrated knife, carefully slice each log into ½-inch-thick rounds (if you hit a chocolate chunk, slowly saw back and forth through the chocolate). If the cookies break or fall apart, just press them back together — the dough is very forgiving. Place them on the prepared baking sheets about 1 inch apart (they won’t spread much). Sprinkle with flaky salt. Bake until the edges are just beginning to brown, 12 to 15 minutes. Let cool slightly before eating them all.
The cookie dough can be made ahead and stored, tightly wrapped in plastic, up to 1 week in the refrigerator, or 1 month in the freezer. Cookies can be baked and stored in plastic wrap or an airtight container for 5 days.