Preheat oven to 350 degrees F.

Cream the butter and the sugar in a mixer until fluffy, scraping down the sides as needed.

Add eggs one at a time, mixing after each addition. Mix in the vanilla.

In a separate bowl, sift together the flour, cocoa powder, baking soda and salt. Add in batches to the mixer, mixing until combined after each addition.

Fold in the chocolate chips.

Drop by tablespoons onto a parchment lined baking sheet.

Bake for 9 to 11 minutes.

Cool on a baking rack.