In a small bowl, mix sugar and cinnamon and set aside.
Cookie Instructions
Preheat oven to 400 F.
In a medium-sized mixing bowl, mix butter, sugar, eggs, and vanilla.
Mix in flour, cream of tartar, baking soda, and salt until just combined.
Evenly spread dough onto a half sheet pan (12.5" x 17") lined with parchment paper or a silicone mat.
Sprinkle roughly two thirds of the cinnamon sugar mixture on top of the batter.
Bake for 25 minutes or until the top is browned and a toothpick comes out clean.
Transfer to a cooling rack and sprinkle with the remaining cinnamon sugar mixture.
When cool, cut into squares and serve.
Notes
The dough is sticky, so spreading it in the pan can be tricky. If you have difficulty spreading it with a spatula, try wetting your hands a little bit and use them to press it down.Half the recipe if you are using a quarter sheet pan rather than a half sheet.Store the cut bars in an airtight container at room temperature for up to five days.