I've done a search on here but almost everything involves reconstituting a commercial bran cereal.
I've never really understood why, unless those recipes came about when one couldn't find wheat (or oat) bran readily available in a store. Maybe somebody else knows why.... Even on King Arthur flour they use bran cereal.
I love good bran muffins. My favorites were from a Chicago area grocery store chain called Dominick's. When Dominick's was sold to Mariano's, I asked the bakery manager if they could get the Dominick's recipe, and they did. But they always sell out.
I'd like to make my own, add a few other things (carrots? ginger?) and have them in the freezer.