Preheat oven to 350 degrees. Use parchment paper or a silpat mat to line a baking sheet.
Cream the butter, brown sugar and granulated sugar in a stand mixer until light and fluffy (about 2-3 minutes). Scrape the sides of the bowl to make sure all ingredients are blended.
Add in the egg and vanilla and beat until combined.
Add in flour, cocoa, salt and baking soda. Mix until all combined.
Stir in 3/4 cup chocolate chips. (Save the other 1/4 to top the cookies)
Scoop out 24 equal cookie dough balls (they should be 1 TBSP of dough – I recommend a 1 TBSP cookie scoop).
Top each cookie with a bunch of chocolate chips.
Bake the cookies at 350 degrees or 9 minutes and then let cool on the baking sheet for an additional 10 minutes. Remove cookies to cooling rack.