5 cups flour
4 teaspoons cream of tartar
2 teaspoons baking soda
1 teaspoon salt
1 cup unsalted butter
1 cup vegetable shortening
3 cups sugar
4 large eggs
1 1/2 teaspoons vanilla extract

Cinnamon Sugar (mix together in small bowl and set aside):
1/3 cup sugar
2 tablespoons sugar

Preheat oven to 375 degrees. In medium bowl, whisk together flour, cream of tartar, baking soda and salt and set aside.

With mixer, beat the butter, shortening and sugar at medium speed until light and creamy, 4 to 5 minutes. Beat in the eggs one at a time. Add vanilla.

With mixer on low, slowly add the flour mixture until combined.

With cookie scoop, scoop a ball of dough into hand. Roll dough into a smooth ball and then roll ball around in cinnamon sugar mixture.

Place cookies on cookie sheet, leaving plenty of room for spreading. Bake until lightly browned and puffy, 10 to 12 minutes. Remove from oven when middle of cookie looks just slightly under-done. Let cookies cool on cookie sheet for 2 to 3 minutes and then cool on wire cookie rack.

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