I had a small about of cooked heirloom beans left. I had used most of them for a salad, so I had very few beans and lots of bean broth.
I added a little water to get the pot to soup level and then added some chopped potatoes. After about 15 gentle minutes on medium heat, I had bean and potato soup. Salt, herbs and anything left over in the fridge would be welcome.
This is why one should cook heirlooms. Commodity beans would have required a ham hock or a bouillon cube. Good heirlooms just need water and time.