6 1/2 tablespoons unsalted butter, room temperature
3/4 cup granulated sugar
1 egg, room temperature
1 teaspoon vanilla extract
1 1/4 cup all purpose GF flour (used Better Batter)
3/4 teaspoon xanthan (omit if blend contains it)
1/8 teaspoon salt
3/4 teaspoon ground cinnamon
1/2 teaspoon baking soda
1 teaspoon cream of tartar
Cinnamon sugar mix for rolling (1/4 c sugar + 1 tbsp ground cinnamon)
In a large bowl, place butter, 3/4 cup sugar, egg and vanilla. Beat with handheld mixer until light and fluffy. Add flour, xanthan, salt, 3/4 teaspoon cinnamon, baking soda and cream of tartar to wet ingredients, mixing to combine after each addition.
Transfer dough to large piece of plastic wrap, wrap tightly and refrigerate until firm, about 30-60 minutes. When dough is ready, preheat oven to 375°F, line rimmed baking sheets with parchment paper and set aside.
Divide dough into 18 pieces of roughly equal size. Roll each piece between palms until forms a ball, then press into disc. Toss each disc in cinnamon-sugar mix until well coated. Place balls of dough into freezer about 10 minutes, until firm. Roll each ball of dough in cinnamon-sugar once more and arrange about 2 inches apart on lined baking sheet.
Place the rimmed baking sheets in the center of the preheated oven and bake 8 to 10 minutes, or until they are either pale but flat or a tiny bit crisp around edges. Cool about 10 minutes, then transfer to wire rack.