Brown the butter: Melt butter in a saucepan over medium heat. Whisk constantly. It will foam, then after a couple of minutes, brown on the bottom. Turn off heat when solids are brown and a nutty aroma appears. Pour into a glass mixing bowl to prevent burning.

Add the shortening, granulated sugar, and brown sugar to the bowl with the brown butter and mix until combined. Add the eggs and vanilla, then mix until smooth.

Add the gluten-free measure-for-measure flour, almond flour, cream of tartar, and baking soda to the wet ingredients. Mix until well-combined. Cover the dough and refrigerate for at least 1 hour and up to 2 days.

Preheat the oven to 400°F (200°C). Line a large baking sheet with a silicone baking mat.

In a small bowl, mix together additional sugar and cinnamon for rolling. Shape the chilled dough into rounded 1-inch balls. Roll each ball generously in the cinnamon-sugar mixture and place 2 inches apart on the baking sheet.

Bake for 9-11 minutes until the edges are set but the centers are still slightly soft. Let cool on the baking sheet for 2 minutes, then transfer to a wire rack to cool completely. Enjoy!