Preheat your oven to 350. In a large bowl; beat together your butter and sugar until it's creamy, light and fluffy.
Add the eggs one at a time, beating well after each addition, then add in the vanilla and beat for one minute, until completely combined.
Combine the flour, cocoa powder, baking soda and salt and gradually blend into the butter mixture. Beat for about a minute on low speed, until all ingredients are thoroughly combined. DO NOT OVERBEAT. Add in chocolate chips and stir - do not beat.
Scoop by teaspoonfuls and roll into balls in the palm of your hand. Place about two inches apart on a parchment paper lined cookie sheet, baking for 8 to 9 minutes.
When you remove them from the oven, they will not look done, but they will harden up a bit once they cool down.