Prep the pan and oven: Heat the oven to 350°F (175°C). Line a 9x5-inch loaf pan with parchment and lightly grease the sides.

Mash the bananas: In a large bowl, mash bananas until mostly smooth with a few small bits for texture.

Whisk in wet ingredients: Add eggs, oil, brown sugar, and vanilla. Whisk until well combined and slightly glossy.

Combine dry ingredients: In a separate bowl, whisk the gluten-free flour, baking soda, baking powder, salt, and cinnamon.

Bring it together: Add half the dry mixture to the banana bowl. Stir gently, then add the milk and remaining dry mixture. Mix just until no dry pockets remain. Do not overmix.

Add mix-ins (optional): Fold in chocolate chips or nuts with a few gentle strokes.

Fill the pan: Scrape the batter into the prepared loaf pan and smooth the top. For a bakery look, run a thin line of oil down the center with a knife.

Bake: Bake for 50–60 minutes, or until the top is golden, the loaf springs back lightly, and a tester comes out with a few moist crumbs.

Cool properly: Let the loaf cool in the pan for 10 minutes, then lift it out to a wire rack. Cool at least 45 minutes before slicing to set the crumb.