Preheat the oven to 375 degrees.
In a small saucepan, bring the water and raisins to a boil. Boil until most of the liquid is gone, about 4 minutes. Move the raisins and remaining water into a food processor or blender. Add in the rum, if using. Puree until smooth. Set aside to cool.
In a small bowl, sift together the flour, baking soda, and salt. Set aside.
In a medium bowl, combine the raisin puree, honey, molasses, and oil, and mix until smooth.
Gradually add in the egg and egg yolk, then buttermilk, and then the oat bran.
Add the flour mixture to the bowl and stir until moistened.
Before filling the loaf or jumbo muffin pan, grease the inside of the pan, then brush the glaze you made previously generously along the inside of it.
Fill the loaf pan with the batter. Brush some glaze over the top of the batter.
Bake for 25-35 min (for muffins) or 38 - 43 minutes (for a loaf), or until the middle part of the loaf sets.
Let the loaf/muffins cool for 2 minutes, then invert onto a rack. Optionally, brush with another layer of glaze.
Enjoy!