Preheat oven to 375°F (190°C).
In a mixing bowl, cream together the butter and 1 cup of sugar until light and fluffy.
Beat in the egg and vanilla extract.
In another bowl, whisk together the gluten-free flour, baking powder, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
In a small bowl, mix the 2 tablespoons of sugar and ground cinnamon.
Roll the dough into 1-inch balls, then roll each ball in the cinnamon-sugar mixture.
Place the coated dough balls onto a baking sheet, spacing them about 2 inches apart.
Bake for 8-10 minutes, or until the edges are lightly golden.
Allow cookies to cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.