1Heat oven to 400°F. Line cookie sheets with cooking parchment paper.
2In medium bowl, mix flour, cream of tartar, baking soda, salt and 1 teaspoon of the cinnamon; set aside. In large bowl, beat butter and granulated sugar with electric mixer on medium speed until light and fluffy. Beat in eggs. On low speed, beat in flour mixture until blended.
3In small bowl, mix green sanding sugar and 1/2 teaspoon cinnamon. In another small bowl, mix red sanding sugar and remaining 1/2 teaspoon cinnamon. Shape dough into 1 1/4-inch balls. Roll half of the balls in green sugar mixture; roll remaining balls in red sugar mixture. On cookie sheets, place balls 2 inches apart.
4Bake 12 to 14 minutes or until set. Cool 2 minutes; remove from cookie sheets to cooling racks.