Stir together flour, splenda, powdered milk, baking powder, baking soda, cinnamon, nutmeg, and salt in a small bowl. Set aside.
In a large mixing bowl, combine bran cereal, oatmeal and skim milk. Cover bran and oatmeal with as much of the liquid as possible and let stand for about 5 minutes, or until most of the liquid is absorbed.
Once bran is softened, add egg, oil, fruit and/or nut mixture, beat well. (You don't need an electric mixer, wooden spoon works fine) Add the flour mixture, stirring "only" until combined. DO NOT OVER MIX! Batter will be lumpy. Put even amounts of batter into 12 muffin tins that you coated with non-fat cooking spray.
Bake at 400 for 20-25 minutes or until golden brown.