Begin by adding 1 cup of pure pumpkin puree to a large mixing bowl. To this, add 1 teaspoon of baking powder, 1 teaspoon of baking soda, 1 teaspoon of pumpkin pie spice, 1 teaspoon of ground cinnamon, and 1/4 teaspoon of salt. Stir these ingredients together until well combined, allowing the spices to blend evenly with the pumpkin.
Add 1 cup of brown sugar and 1 teaspoon of vanilla extract into the pumpkin mixture. Stir until the mixture becomes smooth and well-blended.
Once the mixture is smooth, add 3 eggs and 1/3 cup of melted butter. Mix thoroughly until the ingredients are well combined and the batter takes on a creamy consistency.
Gradually mix in the 1 1/2 cups of gluten-free flour. The batter will be thick, which is to be expected. Be sure to scrape down the sides of the bowl with a spatula to ensure that all of the flour is incorporated.
Lightly grease a loaf pan with either cooking spray or butter. Pour the prepared batter into the pan, smoothing it out to ensure an even bake.
Place the loaf pan in a preheated oven at 350°F. Bake for approximately 55 to 60 minutes, or until a toothpick inserted into the center of the loaf comes out clean.
Allow the bread to cool for a few minutes in the pan before transferring it to a cooling rack.
Cool for 15 minutes
Serve and Enjoy!