Preheat oven to 375F. Line a baking sheet with parchment paper.
In a food processor, add the gluten-free flour, xanthan gum (if using), baking powder, cinnamon and salt. Pulse to combine.
Then, add in the very cold butter chunks and pulse until the butter is the size of small peas. If you don't have a food processor you can also do this in a bowl with a pastry blender or two knives.
Then, add in the vanilla and apple cider. Start with 1/4 cup of apple cider and keep adding more until the mixture is slightly wet and can be held together into a dough (I ended up using a full 3/4 cup of apple cider but it will depend on your brand of flour).
Stir in 1 cup of chopped granny smith apple.
Pat the dough into a circle (about 8 inch in diameter). Cut it into 8 wedges and place on baking sheet lined with parchment paper.
Mix together 1 teaspoon granulated sugar and 1/4 teaspoon ground cinnamon. Sprinkle over the tops of the scones.
Bake at 375F for 15-17 minutes, until they are a light golden brown.
Remove the scones from the oven and allow to cool before glazing.
Mix together powdered sugar, apple cider and cinnamon in a small bowl until smooth. Add any additional apple cider if needed to thin out the glaze.
Drizzle or spoon the cinnamon glaze over the scones and allow to set completely before serving.