2. Sift the flour, sugar, baking soda and salt together.
3. Whisk together the eggs, buttermilk and bran flakes. Let stand for 10 minutes.
4. Make a well in the center of the dry ingredients and add the egg mixture all at once. Stir with a wooden spoon until the dry ingredients are just moistened.
5. Fold in the mashed banana, taking care to keep the mixing to a minimum; some lumps are fine. Fill the muffin tins two-thirds full.
6. Bake in the prepared muffin tins for about 25-30 minutes. The muffins are done when a paring knife inserted in the center of the muffins comes out clean.