Preheat oven to 350 degrees F. Grease a 9-inch x 13-inch baking pan with non-stick cooking spray.
In a medium-sized bowl, whisk together flour, baking powder, cream of tartar, cinnamon and salt. Set aside.
In a large bowl mix together butter until creamy using an electric mixer (or a stand mixture). Mix in sugar and brown sugar and beat until light and fluffy, approximately 3 -4 minutes. Mix in eggs, one at a time, and then the vanilla, and mix until smooth.
Add flour mixture to wet ingredients and mix until well combined.
Spread cookie bar batter out in the prepared baking pan.
In a small bowl, mix 3 tablespoons of sugar and 2 teaspoons of ground cinnamon together and then sprinkle evenly over the top of the batter.
Bake for 25 to 30 minutes or until a toothpick inserted in the center comes out clean. Remove from oven and allow cookie bars to cool. Cut into 20 bars before serving.