Preheat oven to 200ºF.

Coat a large baking sheet with cooking spray; coat with a light dusting of flour and shake off excess.

In a large mixing bowl, beat egg whites, cream of tarter, and vanilla,  with an electric mixer until soft peaks form. Gradually add sugar (1 tablespoon at a time) and beat until stiff, glossy peaks form; gently fold in chocolate chips. You can tell when meringue is ready if you take some of the mixture and rub it between your fingers. If you still feel sugar, then they aren't ready yet. 

Drop mixture by heaping tablespoons onto prepared baking sheet about 1 inch apart, making 24 cookies.

Bake until lightly golden and no longer sticky on the surface, about 1 hour. Turn oven off and let cookies sit in the oven for 1 hour. Transfer cookies to a wire rack to cool completely. Yields 1 cookie per serving.