Directions

1. In a medium bowl, stir together flour, cream of tartar, baking soda, salt and, if you like, cinnamon; set aside.
2. In a large bowl, beat butter with an electric mixer on medium speed for 1 minute. Add sugar; beat for 2 minutes, scraping sides of bowl occasionally. Add egg and vanilla; beat for 2 minutes. With mixer running on low speed, slowly add half of the flour mixture and beat until just combined. Using a wooden spoon, stir in the remaining flour mixture.
3. Knead dough gently in bowl until it just comes together. Divide dough in half and form each half into a 4-inch disk. Wrap each disk in plastic wrap. Chill dough in the refrigerator about 1 hour or until easy to handle.
4. Line 2 large cookie sheets with parchment paper; set aside.
5. On a lightly floured surface, roll one of the dough disks with a floured rolling pin until about 1/4-inch thick. (Keep the other disk in the refrigerator until needed.) Cut dough with a 3-1/2- to 4-inch mitten-shaped cookie cutter or desired shape cutter. Reroll scraps as necessary.
6. Bake, one cookie sheet at a time, in a 350 degree F oven for 11 to 13 minutes or until cookie edges are firm and bottoms are lightly brown. Cool cookies on parchment paper-lined sheet for 1 minute. Transfer cookies to wire racks; cool. Repeat with remaining dough.
7. Frost cooled cookies with your favorite frosting. Makes 8 to 10, 3-1/2- to 4-inch cookies.