Preheat the oven to 400 F.
Grease a 12-cup muffin tin.
. Place half boiling water over the raisins and let set for 15 minutes
Whisk together the all-purpose flour, whole wheat flour, baking soda, and cinnamon in a large bowl.
Stir in the remaining bran cereal, brown sugar, granulated sugar, and raisins.
In a separate bowl whisk the egg.
Add the vegetable oil, buttermilk, and lemon juice. Whisk.
Make a well in the centre of the dry ingredients.
Pour the liquid into the centre and stir until just combined.
Gently fold in the moistened bran.
Fill each muffin tin ¾ full.
Bake in the oven for between 20-25 minutes.
Cool muffins slightly, then unmold and place on a baking rack.