1) Puree the banana, soymilk with vinegar, oil and sugar with a hand blender (me plugging the hand blender again - the best kitchen tool ever!)
2) In a large bowl, stir the dry ingredients together (bran, flour, baking powder and soda, egg replacer powder, and salt). Pour the wet into the dry and mix just until combined. Fold in raisins and walnuts.
3) Divide into 12 muffin tins sprayed with cooking spray or lined with paper liners (note - they'll stick to the paper until a few hours after they've cooled)
4) Bake at 375 degrees Fahrenheit for 15 to 20 minutes (I do mine for 18 minutes).
5) Remove from pan as soon as you can or condensation will collect inside (as with any muffin)...I remove mine almost immediately if I have paper liners - bit hard on the fingers though ;)
I bring these to work all the time...make them on Sunday and they keep pretty well, even unrefrigerated, for the whole work week.
Source of recipe: adapted from http://allrecipes.com/Recipe/Classic-Bran-Muffins/Detail.aspx [1]