Step 1

Prepare the vegetables. Dice the following (no larger than 1/2-inch), keeping them separate: 1 medium yellow onion (about 1 cup), 6 medium stalks celery (about 2 cups), 1 large zucchini (about 2 cups), 3 peeled medium carrots (about 1 1/4 cups), and 1 peeled small sweet potato (about 2 cups). Finely chop 2 garlic cloves. Drain and rinse 1 can white beans.

Step 2

Sauté the mirepoix. Place 2 tablespoons olive oil and 2 tablespoons unsalted butter in a large stockpot or Dutch oven over medium-high heat. Once the butter melts and begins to sizzle, add the onion and 1 teaspoon kosher salt, and sauté until softened but not browned about 3 minutes. Add the carrots and celery and cook until brightened in color, 3 to 5 minutes.

Step 3

Sauté the vegetables. Add the sweet potato and sauté until slightly softened at the edges, about 3 minutes. Stir in the zucchini and garlic, and cook until softened, about 2 minutes.

Step 4

Add seasonings, tomatoes, and broth. Add 1 (2x3-inch) Parmesan rind, 1 can diced tomatoes and their juices, 6 cups chicken or vegetable broth, and the beans. Stir to combine and bring to a boil over medium-high heat.

Step 5

Simmer for 30 minutes. Reduce the heat to medium-low and simmer until the carrots and sweet potato are tender, 20 to 30 minutes.

Step 6

Remove the Parmesan rind. Remove and discard the Parmesan rind.

Step 7

Stir in the pesto, lemon juice, and greens. Squeeze in the juice from 1/2 lemon (about 1 tablespoon). Stir in 2 tablespoons basil pesto and 4 cups baby spinach or baby kale and simmer until combined and the greens wilt. Taste and season with salt as needed.

Step 8

Serve the soup. Ladle the soup into bowls. Thinly shave Parmesan cheese with a Y-peeler and scatter onto the soup, and drizzle with more pesto. Serve with crusty bread.