Is winter STILL here? Vignarola revisited

This is a miserable winter. Cold. Snowy. Cold. I am over it. Today, some friends ran a half marathon in 14 degree weather. May the gods bless them. Me? I stayed home and made soup. As I will explain.
Vignarola has resonance for Romans, in the same way the dish ciambotta (pronounced JamBOAT by my clan) does for southern Italians. To review, ciambotta is "just" a vegetable stew that varies, depending on what you have, as long as you have lots of slow cooked onions. My Nana and Aunts used to eat huge pots of the stuff, with big chunks of bread.
Vignarola is a stew of the spring. And if you speak to Romans, you will hear different variations of it, but there are always peas, and always artichokes in it. Classically, there are also fava beans. All come into season about the same time in Rome, for just a few weeks. You have to make it when you can. Some variants use asparagus, and some use some meat products. When I wrote about this dish, in 2008, I was using asparagus.
Today, I did it differently. I made soup. I wanted something to remind me that spring WILL come, but I wanted winter heartiness. So, I resorted to that standard winter vegetable for rib sticking power: potatoes. The resulting soup, as I lay it out to you, is NOT pretty to look at: think green mud. But it sure is GOOD. And it does taste a bit of spring, with the heft that the potatoes give to it.

None of the vegetables are in season right now, but since Annalena very craftily froze great quantities of peas and fava beans when they were in season, all she needed were artichokes. If you haven't done your own freezing, you can bite the bullet and use frozen veggies. Frozen favas are very difficult to find. If you must, use canned. I did read a very interesting idea, though. A Roman cook posted a blog entry where she used frozen edamame, the green soy beans. Hmmm. So, play with it. Use my recipe if you like, but think of your own variations.

Slice up an onion and chop it, and then peel and chop up about a pound of potatoes. Cover the bottom of a pot with olive oil and add the onions and potatoes. Add a teaspoon of salt, and cook them for about five minutes, while you ready the vegetables. I used just about a pound of each. Get them into the pot, together with a quart of chicken stock (or, water, if you're going completely vegetarian), and then let them cook, slowly, for twenty minutes or so. The toughest vegetable in this pot is the artichoke, so test the doneness of those. If they are soft, everything is ready. Let the pot rest for twenty minutes, and then get a blender out. This is a workout for your blender, so work in small batches, and if you know you don't want a really thick soup, have some water or stock ready to thin it, and to help those blades move the stuff around. Taste it, and correct for salt.

If you want to liven this soup up, grate some lemon peel, or chop some dill, or use both. And, as I say, if the thickness bothers you or you just like something thinner, feel free. There are as many points of view on this one as there are on ciambotta. Since it's a Roman dish, however, the debate will be much more civilized (I guess).