Preheat oven to 325 degrees. Line a cookie sheet with parchment paper.
Beat together butter, sugar and brown sugar until creamy.
Add egg and vanilla extract. Beat until well blended.
Add flour, baking soda and salt. Beat until dough forms a ball.
Remove ball from mixing bowl and split into 3 equal portions.
Leave one of the portions of dough plain.
Add dutch processed cocoa to one of the portions of dough.
Add black cocoa to the last portion of dough.
Roll ½ teaspoon size dough balls with each type of dough.
Take one dough ball from each of the three types of dough and roll them together.
Bake in preheated oven for 8-10 minutes or until edges start to become golden.
Remove cookies to a cooking rack.
