Directions

1. Preheat oven to 350 degrees F. In a medium bowl, whisk together flour, cream of tartar, baking soda, salt and 1 teaspoon of cinnamon, set aside. In a small bowl add 1 1/2 teaspoon cinnamon and 1 tablespoon sugar and mix well, set aside.
   
2. In the bowl of a standing mixer add 1 1/2 cups sugar and the butter and beat on medium for 2 minutes, until smooth and slightly fluffy. Scrape down bowl as needed. Add eggs and beat until smooth. Add in flour mixture and beat until combined.
   
3. Spread dough evenly into a 10-inch cast iron skillet. Sprinkle top with the small bowl of cinnamon/sugar. Place into the oven and bake for 35 minutes, until set. Remove and let cool before serving.