Preheat oven to 400 degrees F.
In a bowl combine the flour, cream of tartar, baking soda, and salt.
In the bowl of your mixer add the butter, shortening, and two types of sugar. Cream together until fully combined.
Add the eggs one at a time followed by the vanilla. Mixing until the are fully combined.
Slowly add the flour mixture ½ cup at a time until the dough is fully mixed together.
Remove dough from the bowl of the mixer and shape into a disc. Wrap in plastic wrap and place in the refrigerator for at least 30 minutes to chill.
Once dough is ready remove from the refrigerator and measure it out by the tablespoon full, rolling it into a ball.
In a small bowl combine the sugar and cinnamon and then roll each ball of dough in it to coat them.
Place the dough balls at least 2 inches apart on a lined baking sheet and bake at 400 degrees F for 8-10 minutes, or until the edges are slightly brown. Once baked remove from baking sheet and place on cooling rack to cool completely.