Step 1

Heat oven to 300°F. Cover cookie sheet with silpat or nonstick silicone pad.

Step 2

Using a mixer, beat the egg whites and cream of tartar together in large bowl at high speed until soft peaks form. Gradually add sugar a little at a time, then vanilla, beating well after each addition until you get stiff peaks, the sugar is dissolved and the mixture is glossy.

Step 3

Sift cocoa onto egg white mixture; gently fold until combined.

Step 4

Fold in chocolate chips. Drop mixture by heaping tablespoons onto cookie sheet. Makes 30 to 32 cookies.

Step 5

Bake 34 to 40 minutes or just until dry. Cool slightly; remove from cookie sheet. Cool completely on wire rack. Store covered, at room temperature.