First, preheat the oven to 350°.
Cream together the butter and sugar in a medium bowl. Then add the vanilla and one egg at a time. Beat on low with a mixer.
In another bowl, sift together the flour, Hershey's cocoa, baking soda, and salt. Add the flour mixture into the butter mixture slowly, and beat it until it's well-blended. Add the chocolate chips and mix again.
Spoon the cookie batter about 2 inches apart onto a cookie sheet. Bake for about 10-12 minutes. Allow them to cool for a couple of minutes and then serve warm.