Preheat oven to 375 degrees F. Line 6 muffin cups with paper liners. For larger muffins, use only 5.
In a mixing bowl, mix together the wheat bran, oat fiber, flour, baking soda, salt, cinnamon and allulose.
Make a well in the center of the dry mixture and add the egg, oil, molasses, buttermilk and prune puree along with the vanilla extract and maple extract. Stir the liquid ingredients together in the well, then incorporate all of the dry ingredients and stir until evenly blended.
Stir in raisins or dried fruit (if using)
Divide the batter between the muffin cups.
Bake at 375 for about 18 minutes. You can bake longer if you need to, but they should be done in 18 minutes.
Let the muffins cool for at least ½ hour. They improve as they cool, so if you want to eat one warm it's best to make them ahead, let cool and then toast or warm in the oven.