Instructions

• Preheat the oven to 350°F (175°C). Line a large baking sheet with a Silpat or parchment paper and set aside.
• In a large bowl, whisk together 2 1/4 cups all-purpose flour, 1/2 cup unsweetened cocoa powder, 1 teaspoon baking soda, 1 teaspoon cream of tartar, 1 teaspoon ground cinnamon, and 1/2 teaspoon sea salt. Set the dry mix aside.
• In the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), beat 1 cup unsalted butter at room temperature until smooth, about 30 seconds.
• Add 1 cup packed brown sugar and 1/2 cup granulated sugar to the butter and beat on medium speed until light and fluffy, about 2 minutes. Scrape down the bowl and paddle.
• Add 2 large eggs and 1 teaspoon vanilla extract to the butter-sugar mixture and mix just until combined.
• With the mixer on low, add the dry ingredients to the wet ingredients in two additions, mixing only until just combined and no streaks of flour remain. Do not overmix.
• In a small bowl, combine 1/4 cup granulated sugar and 1 1/2 teaspoons ground cinnamon; stir until well blended.
• Using about 2 tablespoons of dough per cookie, form dough into balls (a cookie scoop or two-tablespoon measure works well).
• Roll each dough ball in the cinnamon-sugar mixture so each is evenly coated.
• Place the coated dough balls on the prepared baking sheet about 2 inches apart to allow for spreading.
• Bake for 8–10 minutes, until cookies are set around the edges but still soft in the center. Do not overbake.
• Let the cookies cool on the baking sheet for about 5 minutes, then transfer them to a cooling rack to cool completely.