Preheat oven to 400 degrees. Start by adding room temperature butter, 3/4 cup sugar, and egg to your Braun MultiQuick 9. Blend until light and fluffy.
In a medium bowl, mix flour, cream of tartar, salt, and baking soda. Add a little at a time to the MultiQuick 9 pulsing as you add. Once all combined, add vanilla and pulse a little more.
Shape dough into round balls about 1 tablespoon each. Mix 2 tsp sugar and 1 tsp ground cinnamon on a small plate. Roll dough balls in mixture and add to a parchment lined baking sheet. Bake at 400 degrees for 8 minutes or until done. Remove from oven and use a spatula to lift from parchment. Allow to cool completely before adding buttercream.