1. Heat oven to 300°F. Cover cookie sheet with parchment paper.
2. Beat egg whites and vanilla in large bowl on high speed of mixer until foamy. Beat in sugar, 1 tablespoon at a time, beating until stiff glossy peaks form. Sift about half of cocoa over egg whites; gently fold just until combined. Repeat with remaining cocoa.
3. Spoon mixture into pastry bag fitted with large star tip; pipe 1-inch diameter stars onto prepared cookie sheet.
4. Bake 25 to 30 minutes or until dry. Cool slightly; peel paper from cookies. Cool completely on wire rack. Line tray or cookie sheet with wax paper. Prepare CHOCOLATE MINT GLAZE. Dip half of each cookie into glaze; place on prepared tray until set (refrigerate, if desired). Store, covered, in refrigerator. 6 dozen 1-inch cookies.
CHOCOLATE MINT GLAZE: Place 1 cup HERSHEY'S SPECIAL DARK Chocolate Chips or HERSHEY'S Semi-Sweet Chocolate Chips and 4 teaspoons shortening (do not use butter, margarine, spread or oil) in small microwave-safe bowl. Microwave at MEDIUM (50%) 1 minute or until chips are melted and mixture is smooth when stirred. Stir in 4 to 6 drops of mint extract. Use immediately.