How to Make It
In a large saucepan, heat the oil over moderate heat. Add the onion, carrots, and 1/2 teaspoon of the salt and cook, stirring occasionally, until the vegetables start to soften, about 5 minutes.
Add the garlic, zucchini, yellow squash, broth, tomatoes, and the remaining 1 1/4 teaspoons salt; bring to a simmer. Add the Jerusalem artichokes and return to a simmer. Reduce the heat and simmer, partially covered, until the vegetables are tender, about 10 minutes. Stir in the beans, parsley, pepper, and zest.
If you don’t want to tackle the job of peeling knobby Jerusalem artichokes, just scrub them well with a vegetable brush under running water and leave the peel on.