01 - 
                Preheat oven to 350°F (175°C). Line a 9x13 inch baking pan with parchment paper, leaving some overhang on the sides for easy removal, or spray with non-stick cooking spray.
              
              
              
                02 - 
                In a small bowl, mix together the 2 tablespoons of sugar and 2 teaspoons of cinnamon. Set aside.
              
              
              
                03 - 
                In a large bowl, cream together the softened butter and 2 cups of sugar until light and fluffy, about 2-3 minutes.
              
              
              
                04 - 
                Beat in the eggs one at a time, then stir in the vanilla extract.
              
              
              
                05 - 
                In a separate bowl, whisk together the flour, cream of tartar, baking soda, and salt.
              
              
              
                06 - 
                Gradually add the dry ingredients to the wet ingredients, mixing just until combined. The dough will be thick.
              
              
              
                07 - 
                Spread the dough evenly into the prepared baking pan. This can be a bit tricky as the dough is sticky - using slightly dampened hands or a spatula helps.
              
              
              
                08 - 
                Sprinkle the cinnamon-sugar mixture evenly over the top of the dough.
              
              
              
                09 - 
                Bake in the preheated oven for 25-30 minutes, or until the edges are lightly golden and a toothpick inserted in the center comes out with a few moist crumbs (not wet batter). Do not overbake if you want chewy bars.
              
              
              
                10 - 
                Allow the bars to cool completely in the pan on a wire rack before cutting into squares.