Prep the pan and air fryer: Lightly grease a 6x3-inch mini loaf pan (or another small pan that fits your basket). Line with a strip of parchment for easy lifting. Preheat your air fryer to 320°F (160°C) for 3–5 minutes.

Mash the bananas: In a medium bowl, mash the bananas with a fork until mostly smooth with small lumps. You should have about 1 cup of mashed banana.

Whisk the wet ingredients: Add the melted butter (or oil), egg, vanilla, and Greek yogurt to the bananas. Whisk until combined and glossy.

Combine the dry ingredients: In a separate bowl, whisk the flour, sugar, baking soda, salt, and cinnamon.

Mix the batter gently: Add the dry mixture to the wet and stir with a spatula just until no dry streaks remain. Fold in 1/3–1/2 cup of mix-ins if using. Do not overmix—it can make the bread tough.

Fill the pan: Scrape the batter into the prepared pan and smooth the top. If you like, sprinkle a little sugar or a few nuts on top for crunch.

Bake: Place the pan in the air fryer basket. Cook at 320°F (160°C) for 28–36 minutes, depending on your air fryer and pan size. Start checking at 28 minutes.

Check doneness: A toothpick inserted in the center should come out with a few moist crumbs but no wet batter. If the top browns too quickly, tent loosely with foil and continue cooking.

Cool properly: Let the loaf rest in the pan for 10 minutes, then lift it out and cool on a rack for at least 20 more minutes before slicing. This sets the crumb and prevents crumbling.

Serve: Enjoy warm, plain or with a little butter, peanut butter, or honey. It’s also great toasted the next day.