Preheat oven to 375 Degree F (180 degree C)
In a large bowl beat butter with sugar until mixed. Add egg and vanilla mix well.
In a bowl, whisk the flour, cocoa powder, baking soda and salt and chocolate chips and add to butter mixture.
Mix well to get rid of any lumps.
Drop a rounded scoop on parchment lined baking sheet.
Bake to 10- 12 minutes. Let the tray sit for 2 minutes and remove the cookies to wire rack to cool completely.