Using a food processor and a blender for the potent basil puree gives it an ultra-smooth consistency that helps it blend easily into the vegetable soup.
4 ounces fresh shelled beans, such as cranberry beans (about 1 cup) or 1/2 cup dried black-eyed peas, soaked overnight in cold water and drained
1 bay leaf
2 cups plus 3 tablespoons water
1/2 cup plus 2 tablespoons extra-virgin olive oil
1 medium leek, thinly sliced
1 large shallot, thinly sliced
2 small celery ribs, cut into 1/2-inch dice
2 medium carrots, cut into 1/2-inch dice
1 red bell pepper, cut into 1/2-inch dice
2 thyme sprigs
4 cups chicken stock or canned low-sodium broth
Salt and freshly ground pepper
4 ounces green beans, cut into 1-inch pieces
1/2 cup fresh or frozen corn kernels
2 cups coarsely chopped basil
3 medium garlic cloves, quartered
1 medium zucchini, quartered lengthwise and cut crosswise into 1/2-inch pieces
How to Make It
In a small saucepan, combine the beans with the bay leaf and 2 cups of the water. Cover partially and simmer over low heat until tender, about 20 minutes for fresh beans and 45 minutes for dried. Discard the bay leaf.
Heat 2 tablespoons of the olive oil in a large saucepan. Add the leek, shallot, celery, carrots, bell pepper, thyme and the remaining 3 tablespoons of water and cook over moderate heat until the water has evaporated and the vegetables soften, about 10 minutes.
Add the stock and a large pinch each of salt and pepper; bring to a simmer. Add the green beans, corn and the cooked shell beans along with any remaining cooking liquid. Cover and simmer over low heat until the corn is tender, about 5 minutes.
Meanwhile, in a food processor, combine the basil and garlic and process to a paste. With the machine on, slowly pour in the remaining 1/2 cup of olive oil. Transfer the puree to a blender and blend until very smooth. Scrape the puree into a bowl and season with salt.
Add the zucchini to the soup and simmer just until tender, about 4 minutes. Discard the thyme sprigs and season the soup with salt and pepper. Remove the soup from the heat, stir in the basil puree and serve at once.