Soft, buttery banana muffins warmly spiced with cinnamon and nutmeg, with a tender crumb and the option to fold in nuts or chocolate chips. Simple pantry ingredients and a quick mix-and-bake method make these an effortless breakfast treat.
Preheat oven to 425°F (218°C). Line or grease a 12-cup muffin pan.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, and nutmeg.
In a large bowl (or stand mixer bowl), mash the bananas. Add melted butter, brown sugar, egg, vanilla, and milk; beat or whisk until combined.
Add the dry ingredients to the wet ingredients and mix just until combined. If using, fold in the nuts or chocolate chips. Batter will be thick.
Divide batter evenly among the 12 cups, filling each to the top.
Bake for 5 minutes at 425°F (218°C). Keeping the muffins in the oven, reduce temperature to 350°F (177°C) and bake 16–18 minutes more, or until a toothpick comes out clean (about 21–23 minutes total).
Cool in the pan for 5 minutes, then transfer muffins to a wire rack to cool completely.
Storage: Cover and keep at room temperature for a few days or refrigerate up to 1 week. For longer storage, freeze up to 3 months.