Step 1

Preheat oven to 350 degrees F.

Step 2

Cream together butter, shortening, and 1 1/2 cups granulated sugar. Add eggs and vanilla and mix well. Add the flour, cream of tartar, baking soda and salt and stir until combined.

Step 3

Lightly grease a 9x13'' pan. Press the dough into an even layer on the bottom the pan.

Step 4

In a small cup or bowl, mix the 1 1/2 tablespoons granulated sugar and 1 teaspoon cinnamon. Sprinkle mixture evenly over the top of the dough.

Step 5

Bake for 22-26 minutes (don't over bake!). Remove and allow to cool completely before cutting and serving.