In a separate bowl, whisk together the gluten free flour, baking powder, ground cinnamon, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
In a small bowl, mix together the brown sugar and ground cinnamon for the topping.
Pour half of the batter into the prepared cake pan, sprinkle half of the cinnamon sugar mixture on top, then add the remaining batter and top with the rest of the cinnamon sugar mixture.
Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean.
Allow to cool before serving.
Notes
Store leftovers in an airtight container at room temperature for up to 3 days.
This cake can be served warm or at room temperature.
For a richer flavor, consider adding chopped nuts or chocolate chips to the batter.