For the dough: In a bowl, sift together the flour, baking soda, and cream of tartar. Set aside.
In a separate bowl, cream together the butter and sugar until fluffy. Add the eggs, milk, and vanilla. Mix well. Stir in the dry ingredients.
Form the dough into one-inch balls. Place on a greased baking sheet and flatten.
For the topping: combine the sugar and cinnamon, sprinkle on top of the cookies before baking.
Bake for 8 minutes or until cooked through.
Notes
I increased the amount of topping that the recipe called for since I prefer to roll the cookie dough balls in the cinnamon-sugar instead of sprinkling it on top.
Instead of using a greased cookie sheet, I used parchment paper to keep the cookies from sticking.
You actually want to take them out when they still look and feel underdone, they will stay chewier longer that way.