How to Make It
Preheat oven to 350°F. Grease a 9- x 5-inch loaf pan and line bottom with parchment paper.
In a bowl, mix together gluten-free flour, baking powder, salt, and baking soda. Set aside.
In a mixer, cream together butter and sugar until light and fluffy, about 2 minutes. Add eggs one at a time until fully incorporated. Beat for another 2 minutes. Add vegetable oil, vanilla, and vinegar and beat until fully combined.
Add dry ingredients and mix until combined. Add mashed bananas and mix until fully incorporated.
Pour batter into prepared loaf pan and bake until a toothpick inserted into the middle of the bread comes out clean, 55-60 minutes.
Be sure that the gluten-free flour blend you are using contains xanthan gum. This ingredient in some gluten-free flours acts as a binding and thickening agent, which is essential in replicating the structure of gluten in a bread or cake.