Preheat your oven to 350°Spray an 8” x 4.5” loaf pan evenly with cooking spray. Set aside.
In a medium bowl, measure the gluten free flour mix, pumpkin pie spice, baking powder, baking soda and salt. Lightly mix it together with a whisk. Set aside.
In the bowl of a stand mixer, add the butter and brown sugar and beat well, about 1 minute. Stop the machine and add the eggs, one at a time, beating for 30 seconds after each addition.
In with the sugar mixture, add the pumpkin, buttermilk and vanilla. Beat until the mixture is combined.
The mixture will look like orange batter. (And smell divine!)
All at once, add the flour mixture to the orange batter. Mix the flour mixture in until combined, about 1 minute.
Using a rubber spatula, fold in the pecans, if using.
Using the same rubber spatula, scrape the batter into the prepared pan. Smooth out the top slightly.
Bake in the preheated over until a toothpick inserted in the center comes out clean. Start checking it at about 50 minutes in. The gluten free pumpkin bread could take up to 1 hour and 15 minutes, so extra time is not uncommon.
Cool for 10 minutes before removing from the pan to a wire rack to cool completely.
Make sure all ingredients are at room temperature.
Use a stand mixer for the easiest way to mix the batter.