Preheat oven to 375°F (190°C).
Mix together the wheat bran and buttermilk; let stand.
Combine oil, egg, pumpkin, brown sugar, spices and vanilla. Add to bran-buttermilk mixture.
Combine flour, baking soda, baking powder and salt. Add to first mixture and stir until just blended. Stir in raisins and spoon into prepared muffin cups. Bake for 15 – 20 minutes.
*To substitute for 1 cup (250 mL) buttermilk, use 1 tbsp. (15 mL) lemon juice plus enough milk to make 1 cup (250 mL).