Prep the pan: Heat oven to 350°F (175°C). Line a 9x5-inch loaf pan with parchment, leaving a little overhang, and lightly grease.
Mash the bananas: In a large bowl, mash bananas until mostly smooth with a few small lumps for texture.
Whisk wet ingredients: Add eggs, maple syrup (or coconut sugar), melted oil, vanilla, and milk.
Whisk until well combined.
Combine dry ingredients: In a separate bowl, whisk gluten-free flour, baking soda, baking powder, salt, and cinnamon.
Bring it together: Add dry ingredients to wet and stir with a spatula until just combined. Do not overmix; a few small streaks are okay.
Fold in extras: Gently stir in nuts, chocolate chips, or other mix-ins if using.
Fill the pan: Pour batter into the prepared loaf pan and smooth the top. For a pretty finish, sprinkle with extra nuts or a light dusting of cinnamon.
Bake: Bake for 50–60 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs. If the top browns too quickly, tent loosely with foil for the last 10–15 minutes.
Cool properly: Let the loaf cool in the pan for 10–15 minutes, then lift out using parchment and cool completely on a rack before slicing.
Slice smart: Use a serrated knife for neat slices.
Enjoy plain, or toast with a little butter or nut butter.