Preheat oven to 350 degrees
Line several baking sheets with parchment & set aside
Whisk together coating ingredients in a small bowl
In a medium-sized bowl, combine flour, cream of tartar, baking soda & salt. Set aside.
In a large bowl, cream butter & sugar together.
Add eggs & vanilla & mix well.
Combine wet & dry ingredients & beat until a creamy dough forms.
Shape dough into balls & roll in cinnamon/sugar mixture
Place on the prepared baking sheet about 2 inches apart
Bake 8-10 minutes. Cool on wire rack at least 20 minutes before transferring to an airtight container.
If adding the glaze, wait until cookies are completely cooled before doing so.
Once cooled, whisk together glaze ingredients & dip cookies into the mixture.
Place on parchment paper to dry before serving.