Pre-heat oven to 400 degrees.  Mix butter, 1 1/2 cups Splenda, and eggs thoroughly.  Blend flour, cream of tartar, soda, and salt; stir into wet mixture. Add 1/4 cup water to moisten.  Shape dough into 1 inch balls.  Roll balls in mixture of 2 tbsp Splenda and cinnamon.  Place 2 inches apart on ungreased baking sheet. Bake 8 to 10 minutes.  Cookies will be puffy at first and will then flatten.    Recipe makes 6 dozen cookies, with 4 carbohydrate grams per cookie.