Vanilla Sandwich Cookies

1. In a medium bowl, whisk together flour, cream of tartar, baking soda and salt, then set aside.
2. In a large bowl, beat butter with an electric mixer. Add sugar and beat until smooth and creamy. Beat in milk and vanilla. Beat in as much of the flour mixture as you can with the mixer. Stir in the remaining flour mixture by hand. Dough will be soft.
3. Divide dough in half. Cover and chill the dough for about 30 minutes or until easy to handle. On a lightly floured surface, roll half of the dough at a time until 1/8 inch thick.
4. Preheat oven to 350 degrees. Using a 3-inch round cookie cutter, cut out circles from the dough. Using a 1-inch round cookie cutter, cut out circles from the centers of half the dough circles. Place dough on greased cookie sheets.
5. Bake cookies for 10-13 minutes or until golden brown. Let cookies cool for 1 minute then transfer to wire racks to cool.
6. Spread the bottoms of the solid cookies with 2 teaspoons of the Vanilla Cream Cheese Frosting. Then top with the cookie that has the center hole. Refrigerate cookies to store.

To make the Vanilla Cream Cheese Frosting, stir together the frosting ingredients until smooth.