1In a large bowl add the flour, sugar, xanthan gum and salt.
2In a medium bowl add the buttermilk, oil and egg. Blend well with a mixer and set aside.
Note: If you don't have buttermilk put 1 tbsp. lemon juice or white vinegar into a one cup measure. Fill with milk to the 1 cup mark. Let sit until it curdles.
3Add wet ingredients to the dry and mix until combined.
4Mix the sugar and cinnamon in a bowl. This is for the toppings.
5Spray a loaf pan with non-stick spray. Add 1/2 the batter to the loaf pan and sprinkle 1/2 the sugar/cinnamon mixture on the batter. Add the rest of the batter and add the rest of the sugar/cinnamon mixture on top of the batter. Run a scewer through the batter to make a swirl pattern.**
6Bake at 350'F for 45-50 minutes in the center of the oven until done. Cool for a few minutes in the loaf pan, then turn it out onto a wire rack until cold. Do not slice until cold otherwise the bread might fall apart.
7** According to GF Kitchen the batter may have varied results depending on the elevation at which you live as well as the humidity of the flour. If your batter is very thick and you are unable to swirl the cinnamon in the batter try this trick:
Spread 1/2 the batter into the loaf pan, using your finger poke holes through out the batter then sprinkle have the sugar on the batter, then spread the remaining batter on top and poke more holes in the batter then sprinkle the rest of the cinnamon sugar on top. Bake as usual.