We didn't use a blender at all. I'm no cook, so I don't know if we did it right ... but I roasted the veggie ends/leavings and some extras (tomatoes, carrots, celery, garlic) and then made the broth with them. Once I strained it, I pulled out the still-good stuff (roasted tomatoes, carrots, etc) to put in the soup later. Once we got the broth hot again, we put everything in (dense to less ... carrots first, mushrooms last) in the next half hour or so. It all ended up pretty mushy, but still soupy.
We did use potatoes, just not any more than anything else. (LOTS of stuff, so not that much) We didn't add any rice, barley, beans, etc. this go round.