I actually spent a bit more time (maybe 2 more minutes) thinking about this soup because I would have preferred barley but my husband doesn't really like it, or at least he doesn't think that he does. He actually prefers white rice but I'm not using that so...
Wild rice seemed like a happy compromise. I also wanted to use lentils and the black ones called to me. They are called Beluga black lentils because they look like caviar. I realized that my soup was going to be awfully dark, so I also added carrot, parsnip, celery and celery root, along with purple potatoes. After the initiail cooking, a peeled and ready to use kabocha squash showed up on my doorstep (you ought to see what shows up here -- usually edible, delicious and free) and that also got added.
Here is my best stab at the recipe. It's a highly adaptable soup so take what you like and leave the rest.
Takes 20 minutes at high pressure with a natural pressure release.