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Heat the oven to 400 degrees F.
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Grease the baking sheets or line with parchment paper.
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Beat the butter, shortening, 1/4 cup granulated sugar, brown sugar, eggs and vanilla in a large bowl with an electric mixer at medium speed until well blended.
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Combine the flour, cream of tartar, baking soda and salt in a medium bowl.
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Beat the flour mixture into the shortening mixture at low speed until combined.
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Shape the dough into 1" balls.
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Mix 1/4 cup granulated sugar and cinnamon in a small bowl.
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Roll the balls in the sugar/cinnamon mixture.
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Place 2" apart on the prepared baking sheets.
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Bake 6 to 7 minutes or until the cookies are puffed and cracked on top and the edges are set. The centres will be soft.
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Allow to cool 1 minute on the baking sheets.
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Remove to a cooling rack.