Adjust an oven rack to the middle position. Preheat the oven to 350°F. Line two baking sheets with parchment paper.
In a medium bowl, combine the flour, cocoa powder, baking soda, and salt.
In the bowl of a stand mixer fitted with a paddle, beat the butter on medium until smooth. Add the 1¾ cups sugar and beat on medium until light and fluffy, 2 to 3 minutes. Add the egg and vanilla and beat on medium until combined. Add the flour mixture and chocolate chips and beat on low until just combined.
Place the remaining 1 cup of the sugar in a medium bowl.
Form the cookies into 3-ounce (85 g) balls (a scant ⅓ cup each). Roll each ball in the sugar and place 6 cookies on each prepared sheet pan. Bake one sheet at a time 11 to 14 minutes, until the edges have set and the centres are puffed and starting to crackle.
Transfer the baking sheet to a wire rack and let the cookies cool completely on the pan.