Cream butter, sugar, eggs and vanilla until light and fluffy.
Combine flour, cocoa, baking soda and salt; add to creamed mixture. Stir in peanut butter chips.
Drop by teaspoonfuls (or tablespoons OR medium size cookie scoops) onto ungreased cookie sheets. Alternatively, chill dough until firm enough to handle and shape into balls. If using chilled dough balls, flatten the tops slightly.
Bake at 350 degrees f for 8-10 minutes or 12 to 14 minutes if making your cookies larger. If you are baking cold dough, it might take a little longer.
Let cool for 1 minute before removing from cookie sheet and placing on wire rack.