1 pound unpeeled zucchini, ends trimmed and diced
1/2 cup extra virgin olive oil
3 tablespoons butter
1 cup onion sliced very thin
1 cup diced carrots
1 cup diced celery
2 cups peeled, diced potatoes
1/4 pound fresh green beans, topped and cut into small pieces (about 4 to an inch)
3 cups shredded cabbage, savoy or regular green
1-1/2 cups canned cannellini beans, drained (If you want to start with your own dried beans, they must be pre-cooked, not just soaked, for this recipe)
6 cups chicken stock
the rind from a large piece of parmigiano-reggiano cheese, carefully scraped and washed.
2/3 cups canned plum tomatoes with their juice
Salt
1/3 cup freshly grated parmigiano-reggiano cheese

Put the oil, butter, and sliced onion into an 8-quart stockpot. Turn the heat to medium/low, and cook the onion until it softens and turns a pale gold. Do not let it color more than this.

The diced vegetables are to be added sequentially, not just plopped into the pot. First, add the diced carrots, and cook for 2 -3 minutes, stirring once or twice. Next add the diced celery and do the same. Then do the same with the potatoes. Now do the same with the green beans. Last, do the same with the zucchini.

Cook them all together for a few minutes, stirring occasionally. Add the shredded cabbage, and continue to cook for another 5 minutes.

Add the chicken stock, the cheese rind, and the tomatoes with their juice. At this point check carefully for salt. How much you need will depend on how much your chicken stock has in it, but be sparing because you can add more when it's cooked down.

Stir thoroughly, cover the pot, and lower the heat so the contents are cooking at a gentle simmer.

After 2-1/2 hours, added the canned drained cannellini beans. Then cook for at least another 30 minutes. This soup should be rather thick, but if it gets too thick while cooking, it can be thinned with a little water.

When it's done, turn off the heat, remove the cheese rind, and swirl in the grated cheese. Taste and correct for salt. Improves with reheating.