Cover a baking sheet with parchment or wax paper; secure with masking tape.
Combine the cocoa and chocolate in a food processor, and pulse 4 times or until the chocolate is finely chopped. Add the powdered sugar and cornstarch, and pulse 2 times or until mixture is well-blended. Beat egg whites and coffee granules in a medium bowl at high speed of a mixer until foamy. Gradually add the granulated sugar, 1 tablespoon at a time, beating mixture until stiff peaks form. Fold in the cocoa mixture and vanilla. Spoon the egg white mixture into a zip-top plastic bag, and seal. Carefully snip off 1 bottom corner of bag. Pipe the egg white mixture into 24 portions onto prepared baking sheet, forming pointed mounds 2 inches wide and 1 1/2 inches high. Bake at 325° for 30 minutes or until dry. Carefully remove the meringues from paper.
Note: Store kisses in an airtight container for up to 2 days.