In a large bowl, use a handheld mixer or a stand mixer fitted with the paddle attachment to beat the softened butter, granulated sugar, and brown sugar together on medium-high speed until the mixture is light, fluffy, and pale in color—about 2 to 3 minutes. Add the egg and vanilla extract, then continue beating on high speed until fully combined. Be sure to scrape down the sides and bottom of the bowl as needed to incorporate everything evenly.
In a separate bowl, whisk together the all-purpose flour, cocoa powder, baking soda, and salt until well combined. With the mixer running on low speed, gradually add the dry ingredients to the wet mixture. Beat on low until just combined, then fold in the chocolate chips. The dough will be thick and very sticky. Cover the dough tightly and refrigerate for at least 3 hours, and up to 3 days—chilling is essential to manage the stickiness and improve the texture.
When ready to bake, remove the dough from the refrigerator and let it sit at room temperature for 10 minutes. If the dough has chilled for longer than 3 hours, allow it to rest for about 20 minutes so it softens slightly, making it easier to scoop and shape.
Preheat your oven to 350°F (177°C). Line large baking sheets with parchment paper or silicone baking mats for best results and set aside.
Using a medium cookie scoop or a tablespoon, portion the dough into balls about 1.5 tablespoons each. Roll each ball lightly in granulated sugar, then generously coat them in confectioners’ sugar. Place the coated dough balls on the prepared baking sheets, spacing them about 3 inches apart.
Bake for 11 to 12 minutes, or until the edges are set but the centers still look soft. If the cookies don’t begin spreading by around minute 9, remove the baking sheet and gently tap it on the counter 2 to 3 times to encourage spreading, then return the cookies to the oven to finish baking.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely. As they cool, the cookies will slightly deflate, creating their classic crinkled appearance.
Store the cookies in an airtight container at room temperature for up to one week to maintain freshness.