Place the flour, bran, sugar and baking powder in a large bowl, and stir to mix well. Set aside.
Place the milk, marmalade, margarine/butter, egg whites and vanilla in a small bowl and stir to mix well. Add the milk mixture to the flour mixture, and stir just until the dry ingredients are moistened. Fold in the pecans or blueberries, if desired.
Coat the bottoms only of muffin cups with non stick cooking spray (I just sprayed the whole thing.go wild!), and fill 3/4ths full with the batter. Bake at 350 for 15 minutes (I used frozen berries and it took a couple of minutes longer) or until a wooden toothpick comes out clean (I actually just lightly push the tops.if they bounce back they're done). Be careful not to overbake.
Remove the tins from the oven, and allow to sit 5 minutes (yeah right). Refrigerating any leftovers not eaten in 24 hours.