In a large bowl, beat the butter and sugars together with an electric mixer.
Add in the eggs, vanilla extract and molasses and beat until fully combined.
In a medium-sized bowl, stir together the flour, cocoa powder, baking soda and cream of tartar.
Beat half of the flour mixture into the butter mixture, then the second half.
Stir in the chocolate chips and sprinkles until completely combined.
Refrigerate the cookie dough for at least 1 hour.
Pre-heat oven to 325F.
Line two cookie sheets with parchment paper.
Portion out the cookie dough onto the prepared sheets with a cookie scoop.
Bake for 12-15 minutes, until tops begin to crack and edges are set.