Chocolate and cinnamon are so wonderful together, especially in the form of these chewy, cinnamon sugar-coated chocolate snickerdoodle cookies. We recommend chilling the dough for 30 minutes or so. This cookie dough is a little sticky, so the chill helps make rolling the dough into balls and then into the cinnamon sugar easy. It also improves the flavor and texture of the cookies in the end.
2 ½ cups (325g) all-purpose flour
1/2 cup (42g) unsweetened cocoa powder
2 teaspoons cream of tartar
1 teaspoon baking soda
1/4 teaspoon fine sea salt
1 cup (226g) unsalted butter, at room temperature
1 ½ cups (300g) granulated sugar
1/2 teaspoon vanilla extract
2 large eggs at room temperature
1 cup (170g) semi-sweet chocolate chips, 6 ounces
1/4 cup (50g) granulated sugar
1 ½ tablespoons ground cinnamon
Sift (or whisk) the flour, cocoa powder, cream of tartar, baking soda, and salt together, then set aside.
Using a handheld mixer at medium speed in a large bowl, beat the butter, sugar, and vanilla until light and fluffy for 3 to 4 minutes. (You can also use a stand mixer fitted with the paddle attachment.)
Reduce speed to low. Add the eggs one at a time, beating well after each addition.
Scrape the sides and bottom of the bowl, then add the flour mixture in three parts, mixing until it disappears.
Stir in chocolate chips. Cover with plastic wrap and chill the dough for at least 30 minutes or up to 3 days.
Preheat the oven to 400°F (204°C). Line two baking sheets with parchment paper or use silicon baking mats.
In a small bowl, mix the sugar and cinnamon.
Shape heaping tablespoon-sized mounds of cookie dough into balls. Roll in the cinnamon-sugar mixture and place 2 inches apart on baking sheets. (A medium cookie scoop is helpful here.)
Bake the cookies until they have puffed a little and the tops look set, 8 to 10 minutes.
Cool on baking sheets for 5 minutes, then transfer to a cooling rack to cool completely. (The cookies will fall slightly as they cool.)