Preheat oven to 350 degrees.
Cream together the white sugar, brown sugar, and butter.
Add the egg and vanilla and mix until light and fluffy, around 2 minutes.
In a separate bowl, whisk together flour, baking soda, cocoa powder, and salt.
Add the dry ingredients to the wet ingredients a little at a time, and mix until just combined.
Stir in the chocolate chips.
Drop by rounded teaspoonfuls onto a baking sheet lined with parchment paper, spaced about 2 inches apart.
Bake about 10 minutes, or until cookies are set but not dark on the edges. Enjoy!