8 medium zucchini
1 medium Spanish onion
6-8 green onions
Leaves from 4 to 6 stems flat-leaf parsley
3 cloves garlic
6 tablespoons extra-virgin olive oil
1¼ teaspoons kosher salt, plus more as needed
¾ teaspoon freshly cracked black pepper
About 6 large basil leaves, plus more for garnish
2 cups water, or more as needed
Freshly grated Parmigiano-Reggiano cheese, for garnish
Trim the zucchini ends, then cut each vegetable into chunks. Finely chop the onion, scallions, parsley and garlic; piling them together is OK.
Heat ¼ cup of the oil in a large Dutch oven over medium-high heat. Once the oil shimmers, add one-third of the zucchini chunks and stir to coat. Cook for a few minutes, just until the bottom side is golden and lightly caramelized, then transfer to a mixing bowl. Repeat two more times (no need to add more oil) to use of all the zucchini.
Add the remaining 2 tablespoons of oil to the pot. Once it shimmers, add the onion-scallion mixture and stir to coat. Season with ¼ teaspoon each salt and pepper. Reduce the heat to medium; cover and cook for about 8 minutes, so the vegetables soften.
Coarsely chop the 6 basil leaves.
Return the zucchini to the pot, then season with the remaining salt and pepper. Stir in the water, which will not quite cover the zucchini. Increase the heat to high and cook just until bubbles form at the edges, then reduce the heat to medium-low, cover and cook for about 12 minutes. The zucchini should be soft but not disintegrating. Stir in the chopped basil.
Use an immersion (stick) blender to purée the mixture into a thick soup that retains some small chunks of zucchini. If it's too thick for your liking, add water as needed. Remove from the heat. Taste, and adjust seasoning as needed.
Divide among individual bowls or deep cups. Tear a few basil leaves over each portion, then grate a little Parmigiano-Reggiano cheese over each one as well. Serve warm or at room temperature.
Serves four to six.
Nutrition values per serving: 180 calories, 14 g fat (2 g saturated), 12 g carbohydrates, 4 g fiber, 6 g sugar, 4 g protein, 0 cholesterol, 430 mg sodium.
Adapted from "Franny's: Simple Seasonal Italian," by Andrew Feinberg, Francine Stephens and Melissa Clark (Artisan, 2013)