Creating your Gluten Free Cinnamon Coffee Cake is simple if you follow these steps:

1. Preheat your oven to 350°F (175°C). Grease and flour a 9×9-inch baking pan or line it with parchment paper.
2. Mix Dry Ingredients: In a large mixing bowl, combine the gluten-free flour, granulated sugar, brown sugar, ground cinnamon, baking powder, baking soda, and salt. Stir well to combine.
3. Cream Butter: In another bowl, beat the softened butter until fluffy. This should take about 2-3 minutes.
4. Add Eggs and Vanilla: Incorporate the eggs one at a time into the butter, mixing well after each addition. Stir in the vanilla extract.
5. Combine Mixtures: Gradually add the dry ingredient mixture to the butter mixture, alternating with the milk. Begin and end with the dry mixture, stirring until just combined and smooth.
6. Prepare Topping: In a small bowl, combine 1 tablespoon of cinnamon, ½ cup of brown sugar, and chopped nuts if using. Set aside.
7. Layering: Pour half of the batter into the prepared baking pan. Evenly sprinkle half of the cinnamon-sugar mixture over the batter. Pour the remaining batter on top, then sprinkle the rest of the cinnamon-sugar mixture.
8. Bake: Place the pan in the oven and bake for 30-35 minutes. A toothpick inserted in the center should come out clean.
9. Cool: Allow the cake to cool in the pan for 15-20 minutes before transferring it to a wire rack to cool completely.
10. Optional Glaze: If desired, mix powdered sugar with a small amount of milk to create a glaze. Drizzle over the cooled coffee cake.

Following these steps will lead you to an incredible Gluten Free Cinnamon Coffee Cake that will impress anyone who tries it!