Prep the pan and oven. Heat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan and line it with a parchment sling for easy removal.

Mash the bananas. In a large bowl, mash bananas until mostly smooth with a few small lumps. You want about 1 1/2 cups.

Whisk the wet ingredients. Add eggs, oil, yogurt, brown sugar, and vanilla to the bananas. Whisk until smooth and slightly glossy.

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

Bring it together. Add the dry ingredients to the wet. Stir gently with a spatula until just combined and no dry streaks remain. Do not overmix.

Add mix-ins. Fold in nuts or chocolate chips if using. The batter will be thick but scoopable.

Fill the pan. Scrape batter into the prepared pan. Smooth the top and sprinkle with coarse sugar for a crackly crust, if you like.

Bake. Bake for 55–65 minutes until the top is deep golden and a tester comes out clean or with a few moist crumbs (no wet batter). If the top browns too fast, tent loosely with foil in the last 15 minutes.

Cool properly. Let the loaf cool in the pan for 10 minutes, then lift it out and cool on a rack for at least 1 hour before slicing. Gluten-free loaves set as they cool; slicing too soon can make the crumb gummy.

Slice and enjoy. Use a serrated knife for neat slices. Serve warm, at room temp, or lightly toasted.