In a mixing bowl, combine butter and sugar until well blended. Add egg and vanilla until combined.
Add gluten free flour, guar or xanthan gum (omit if in blend), salt, baking soda, and cream of tartar. Mix until the dry ingredients are blended in. Cover the bowl with plastic wrap and refrigerate for at least 1 hour.
Preheat oven to 375° F. Line 2 baking sheets with a silicone mat or leave as is, ungreased.
In a small bowl, combine the the cinnamon and sugar to create the sugar topping.
Remove dough from refrigerator and shape into 1-inch size balls. Roll each ball in the sugar topping and place on baking sheet 2 inches apart.
Bake for 9-11 minutes. You don't want to overbake these cookies. They should be slightly gooey on the inside.
Allow to cool slightly on baking sheet before transferring to a cooling rack. Store any leftovers in an airtight container. Yield about 1 ½ dozen cookies.