Preheat your oven to 177 °C (175 °C). Grease a standard 9x5-inch loaf pan and line it with parchment paper for easy removal.

In a medium bowl, whisk together the gluten-free baking flour, baking soda, fine sea salt, and ground cinnamon until fully combined.

In a large mixing bowl, beat the melted butter and brown sugar together until smooth. Whisk in the eggs one at a time, followed by the vanilla extract and Greek yogurt.

Fold the mashed bananas into the wet ingredient mixture until evenly distributed.

Gently add the dry ingredients to the wet mixture, stirring with a spatula just until combined and no dry flour streaks remain.

Pour the batter into the prepared loaf pan and smooth the top evenly with a spatula.

Bake for 50 to 60 minutes, or until a wooden toothpick inserted into the center comes out clean or with a few moist crumbs.

Allow the bread to cool in the pan for 15 minutes, then use the parchment paper handles to transfer it to a wire rack to cool completely before slicing.