This soup is infinitely variable and adjustable. In fact, the only rule is that you can only make it the same way once.
1/4 cup olive oil
1 large onion
1/2 head green cabbage, cut up small
3 celery stalks or a celeriac
3 cloves garlic
Salt and pepper
Red pepper flakes
28-oz can tomatoes, plus some tomato paste or dried tomatoes
2-4 cups cooked beans
1/4 cup dried basil
2 tbsp. dried oregano
pinch of fennel
2 bay leaves
1/2-1 cup cooked grain, or a handful of uncooked rice or wheat pasta
1 head kale, stemmed, finely chopped
1/2 cup chopped parsley (no large stems)
1 cup each frozen peas and corn
The idea with this soup is to layer everything--build on what came before.
First, saute the first group of ingredients in a big soup pot, in olive oil on medium heat, till nicely soft and aromatic. Add potatoes and carrots, and cook another ten minutes, stirring often.
Add tomatoes, beans, and spices, and some water. Bring to a boil, and cook for an hour or more, till the vegetables are fully cooked. At the end, add the grain or pasta; when it's almost cooked, add the greens and frozen vegetables (so they don't get overcooked and lose their color).
Approximate amounts for 2 12-quart stockpots (feeds 70-90 as a side)
6 quarts cooked (3 quarts dry) beans
6 large potatoes
8 28-oz cans tomatoes
3 bags frozen peas
3 bags frozen corn (~16 oz. each for frozen veggies)
2 bunches parsley, chopped