Combine the all-purpose flour, baking soda, cream of tartar, salt and cinnamon in a bowl. Stir these together and set it aside for now.
Combine the butter and sugar together in a mixing bowl, and beat until fluffy.
Add in the egg and vanilla extract, and mix in.
Add the dry ingredient mixture to the mixing bowl, and mix together.
Line a 10 inch cast iron skillet with parchment paper.
Spread the dough into the pan. It will be sticky. I find it easiest if I put my hand inside a plastic bag and then press the dough into the pan that way.
Combine the topping ingredients in a small dish, and stir them together.
Sprinkle the topping all over the top of the dough.
Bake for 25 minutes or until it tests done with a wooden pick.
Cool completely.
Cut into bars, and enjoy!
Notes
If you don't have a 10 inch cast iron skillet, you can bake these in a 9x9 inch baking pan.If you don't wish to use parchment paper, you can simply grease the pan.