Preheat the oven to 350°F.

In a medium mixing bowl, whisk to combine the flour, cocoa powder, baking soda, and salt.

In the bowl of a stand mixer fitted with the paddle attachment, cream the butter, light brown, and granulated sugar on medium speed for about 3 minutes until lightened in color and fluffy.

Add the egg and vanilla and mix on low speed for 30 seconds, just until combined.

With the mixer on low speed, gradually add the flour mixture a few tablespoonfuls at a time, mixing just until combined between each addition. Add the chocolate chips and mix on low speed just until combined.

Scoop cookies to be about 1½ tablespoons in size onto parchment-lined baking sheets, leaving about 2 inches of space between each cookie.

Bake for about 9 minutes. Remove the pan from the oven and tap the cookies on the counter once to flatten the tops. Let them cool on the pan for 5 minutes, then transfer to a cooling rack.