1. Preheat oven to 150 C.
2. Combine egg whites, cream of tartar and vanilla. Beat until the whites form soft peaks. Slowly add sugar; beat until stiff peaks form, and mixture becomes glossy.
3. Fold in cocoa and chocolate chips.
4. Drop mixture by teaspoonfuls on to a greased baking tray. Bake for 25 to 30 minutes.