4 T olive oil
1 onion, 3 scallions, or 1 leek (trimmed and well rinsed), chopped
2 carrots, 2 parsnips, or 2 turnips, roughly chopped
2 zucchini, 2 yellow squash, or 2 small bell peppers, roughly chopped
1c corn kernels (frozen are fine), fresh or frozen beans (lima, fava, edamame), or fresh or frozen peas
8oz spinach, cabbage, broccoli, or other leafy green or cruciferous vegetable, chopped
Salt and black pepper
1c cored, chopped tomatoes (canned are fine; include their juice)
1/2c chopped fresh basil, plus more for garnish.
1/2c grated Parmesan cheese, for serving, optional
1. Put 3T oil in a large pot or Dutch oven over medium-high heat. When it's hot, add the onion and carrots. Cook, stirring, until the onion softens and the vegetables begin to color, 10 minutes.
2. Add the zucchini, corn, and spinach; sprinkle with salt and pepper. Cook, stirring, for a minute or two, then add the tomatoes and 6 cups water. Bring to a boil, then adjust the heat so the mixture bubbles gently. Cook, stirring every now and then, until the vegetables are soft and the tomatoes have broken up, about 15 minutes. (The soup can be made up to this point a day or two ahead; gently reheat before proceeding.)
3. Add the 1/2c basil and adjust the heat once again so that the mixture bubbles gently. Cook until all the vegetables are very tender, 5 to 15 minutes longer. Taste and adjust the seasoning and drizzle with the remaining olive oil. Serve.
Source: The Food Matters Cook Book by Mark Bittman