ingredients

• 2¼ c. all-purpose flour
• 2 t. cream of tartar
  
• 1 t. baking soda
• ½ t. salt
• ¾ c. (1½ sticks) softened sweet butter
• ¼ c. shortening
• 1½ c. sugar, plus 3 T. for rolling cookies
• 2 eggs
• 1 T. ground cinnamon, for rolling cookies

directions

1. Preheat oven to 400 degrees.
   
2. Mix flour, cream of tartar, baking soda and salt together.
3. Cream butter, shortening and 1½ cups sugar until combined. Scrape down sides of bowl with rubber spatula.
4. Add eggs and beat until combined.
5. Add dry ingredients and beat at low speed until just combined.
6. Mix remaining 3 tablespoons sugar with cinnamon in a shallow bowl.
7. Roll dough into balls, using 2 scant tablespoons per ball. Roll balls in cinnamon sugar and place on two lined (parchment or silicone baking mats) cookie sheets.  Leave at least 2 inches between cookies to allow for spreading during baking.
   
8. Bake for about 9 to 11 minutes.  If you're not using a convection oven, halfway through swap cookie sheets, turning them 180 degrees as you swap.  When done, the cookies' edges will have begun to set and the centers will be soft and puffy.
9. Let the cookies cool on the sheets for a few minutes before transferring them to cooling racks.