Position a rack in the middle of the oven and preheat to 350°F (180°C). Generously grease 24 mini muffin cups with nonstick cooking spray or grease with butter.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt. In another bowl, stir together the buttermilk, egg, 2 tablespoons maple syrup, and the butter until just combined. Add the wet ingredients to the dry ingredients and stir until combined. Stir in the mashed banana.
Spoon the batter into the prepared muffin cups. Bake until the muffins are puffed and golden, 10–12 minutes. Let the muffins cool slightly in the pan on a wire rack, then unmold onto the rack. Serve right away with maple syrup for dipping.
This recipe is excerpted with permission from <a href="http://www.amazon.com/gp/product/1616282002/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1616282002&linkCode=as2&tag=craftfocom-20">"Home Baked Comfort (Williams-Sonoma): Featuring Mouthwatering Recipes and Tales of the Sweet Life with Favorites from Bakers Across the Country"</a> by Kim Laidlaw and published by Weldon Owen.