Preheat oven to 350℉. Spray a 9x5-inch baking pan with nonstick cooking spray. (Optional: Line pan with parchment paper and spray with cooking spray.)

Mash the bananas until almost smooth in a small bowl with a fork. Set aside.

Whisk together gluten-free flour, baking powder, baking soda, and salt in a medium bowl.

In a large bowl, mix softened butter, sugar, and vanilla extract until light and creamy. Add the eggs one at a time. After you add the last egg, mix until it's smooth and creamy, about two minutes.

Add the mashed bananas. Stir to combine.

Mix in the dry ingredients. Stir until a batter forms.

(If you're adding chocolate chips, nuts, or dried fruit, add them now.)

Spread the batter into the prepared pan.

Bake until a cake tester inserted into the middle of the loaf comes out clean, about 65 minutes.

If the top browns too quickly and the center isn't done, cover the loaf a lightly greased piece of foil. (If the center is baked and top of the loaf is raw, cover with a greased piece of foil and reduce the oven temperature by 25 degrees. Bake until done.)

Remove pan from the oven and place on a wire rack. After fifteen minutes, turn bread directly onto the rack.

Store, wrapped, at room temperature for up to four days or freeze, wrapped tightly in plastic wrap, for up to one month.