In a large mixing bowl add 1/2 cup soft butter, 1/2 cup shorting, 1 1/2 cup sugar, and 2 eggs.
Mix for about 2 minutes.

Then add to the mixing bowl 2 3/4 cups of flour, 2 tsp cream of tartar, 1 tsp baking soda, 1/4 tsp salt.
Mix until dough is thick, scraping the sides as you mix.

Roll dough into a ball with plastic rap and refrigerate for 1 hour.
While dough chills mix 2 tbsp sugar and 2 tsp cinnamon, set aside.
Pre heat oven to 400 degrees

When dough is chilled sharp dough into tbsp sized balls and roll in cinnamon sugar mixture.
Place in ungreased baking sheet 2 inch apart.

Bake 8-10 minutes or until set.
Remove from baking pan immediately and cool on a rack.
Enjoy !!!