Instead of mashing some of the beans to thicken the mix, stir in a small can of refried beans, the real kind made with lard. A restaurant where I used to eat regularly did that with the pinto beans they served on their buffet line.
I actually considered doing that. I have a dozen or so packages of Mexicali Rose dried refried beans that are quite good. Much better IMO that anything in a can. Maybe I'll try it next time.
