Preheat oven to 300 degrees F; line baking sheets with parchment paper or silicone baking mats and set aside.
In a large mixing bowl with a whisk or an electric mixer fitted with the whisk attachment, beat egg whites and cream of tartar until soft peaks form.
Slowly add sugar and vanilla; beat until sugar is dissolved and stuff peaks hold; the mixture should be glossy.
Fold cocoa into egg whites until combined; add chocolate chips and fold until spread throughout mixture.
Drop egg mixture using a tablespoon onto prepared cookie sheets and bake for 35-45 minutes, or until cookies are dry.
Remove from oven and cool completely before serving.