Preheat oven to 400 degrees F. Coat a 12-cup muffin pan with nonstick cooking spray.
Add the bran cereal and buttermilk to a large mixing bowl and stir until the cereal is well coated with milk. Let it rest for several minutes until the cereal softens.
Meanwhile, in a separate medium mixing bowl, combine the flour, sugar, baking powder, baking soda and salt. Set aside.
Add the egg, oil, molasses, and vanilla to the softened bran cereal. Beat for 2 to 3 minutes with an electric mixer to combine and break up the bran cereal a bit. Add the flour mixture all at once and stir with a wooden spoon or spatula just until moistened. Add the raisins and stir to incorporate them throughout the batter.
Divide the batter evenly between the prepared muffin cups.
Bake for 18 to 20 minutes or until golden brown. Cool in the muffin pan for 5 to 10 minutes before removing. Delicious served warm.
