Preheat the oven to 350°F (175°C) and grease a 9x5-inch loaf pan.

In a large bowl, mix the mashed bananas with melted butter, followed by sugar, beaten eggs, and vanilla extract.

In another bowl, whisk together gluten-free flour, baking soda, and salt.

Combine wet ingredients with the dry ingredients and fold in the chopped walnuts.

Pour the batter into the prepared loaf pan and spread evenly.

Bake in the preheated oven for 60 minutes or until a toothpick inserted in the center comes out clean.

Allow the bread to cool for 10 minutes in the pan, then transfer to a wire rack to cool completely.