Pesto White Bean Soup
Tuscan-style, finished with a spoonful of pesto

Two cans of white beans, some vegetables, a carton of broth, and a jar of pesto that has been sitting in the fridge door for three weeks. That is this soup — a Tuscan-style bean soup built entirely from the pantry and fridge, finished with a swirl of herb pesto that turns a quiet bowl of legumes into something with fragrance, color, and a lot more dimension than the ingredient list suggests it should have.

The pesto goes in at the end, in the bowl, not cooked into the soup. This matters. Pesto loses its bright green color and much of its basil fragrance when it is simmered — it turns an unpleasant brown and becomes flat-tasting. Added tablespoon by tablespoon at the table, it keeps all its vivid color and herby sharpness and creates a contrast between the warm, savory soup and the cool, oily pesto. The technique is borrowed from ribollita, the Tuscan bread soup, where a similar herb paste called pesto genovese is swirled in just before eating.

The other technique worth knowing is the half-mash: drain both cans of beans, but mash about a third of them with a fork before adding to the pot. The mashed beans dissolve into the broth and thicken it, so the soup has body and substance without any cream, flour, or roux. The whole beans provide texture. The mashed portion provides richness. It is a simple trick that transforms the mouthfeel of the soup entirely.

What you need

• 2 cans (400g / 14 oz each) cannellini beans or any white bean — drained and rinsed
• 1 tablespoon olive oil
• 1 medium onion, diced
• 2 celery stalks, sliced — if you do not have celery, omit it; the soup is still very good
• 2 carrots, peeled and diced
• 4 garlic cloves, sliced
• 1 can (400g / 14 oz) diced or crushed tomatoes
• 1 litre (4 cups) vegetable broth — or chicken broth if preferred
• 1 Parmesan rind, if available — optional, but adds a savory depth that is hard to replicate
• 1 teaspoon dried thyme or Italian herb blend
• Salt and black pepper
• 4 heaped tablespoons pesto — jarred basil pesto works very well; homemade is better if you have it
• Crusty bread — not optional

How to make it

Step 1: Build the vegetable base. Heat the olive oil in a large pot over medium heat. Add the diced onion, sliced celery, and diced carrot with a pinch of salt. Cook for six to seven minutes, stirring occasionally, until the vegetables are fully softened and the onion is translucent. Add the sliced garlic and the dried herbs. Cook for one more minute, stirring, until the garlic is fragrant. Do not rush this step — the vegetable base is the structural flavor of the soup, and soft, well-cooked vegetables make a noticeably better result than crunchy ones.

Step 2: Add tomatoes. Add the canned tomatoes to the pot. Stir to combine with the vegetable base. Turn the heat up slightly and cook for four minutes, stirring occasionally, until the tomatoes have reduced slightly and the raw tomato flavor has mellowed. You will see the mixture come together into a unified base rather than separate tomatoes floating in oil. This brief cooking time also concentrates the tomato flavor before the broth dilutes it.

Step 3: Add broth and beans. Pour in the vegetable broth. If you have a Parmesan rind, add it now — it will simmer in the soup for the duration of the cooking and add a savory, umami depth that approximates what a ham hock does in a meat-based bean soup. Drain both cans of beans and rinse under cold water. Put about one third of the beans (roughly three quarters of one can) into a bowl and mash them roughly with a fork until they form a rough paste — not completely smooth, some texture is good. Add the remaining two thirds of the beans to the pot whole, then stir in the mashed bean paste. The paste will dissolve into the broth and immediately begin thickening it.

Step 4: Simmer. Bring the soup to a simmer and cook for fifteen minutes, stirring occasionally. By the end of this time, the broth should be noticeably thicker and the vegetables fully tender. Remove the Parmesan rind if you used one — it will have become swollen and soft. Taste the soup and season with salt and black pepper. If it tastes flat, it likely needs more salt. If it seems too thick, add a splash more broth or water. If too thin, let it simmer uncovered for another few minutes.

Step 5: Serve with pesto. Ladle the soup into bowls. Do not stir the pesto into the pot. Instead, drop a heaped tablespoon of pesto into the center of each bowl. It will sit on the surface and spread slightly. Drag a spoon through it once to create a swirl. Serve immediately with good crusty bread — this is how the Italians eat it and the bread is fundamental to the experience.

On which pesto to use

Jarred basil pesto from the refrigerated section of the supermarket works well here — far better than shelf-stable pesto in a jar, which has a cooked, flat character that the soup does not benefit from. If you have a half-jar of any refrigerated pesto — sun-dried tomato, kale, arugula — it will work. Homemade pesto from wilting herbs is ideal and the original version of this combination.

Chef notes

This soup improves significantly when reheated. The beans continue to break down slightly overnight and the broth thickens further. Add a splash of water when reheating and re-season. Add fresh pesto at the table each time rather than stirring it in before refrigerating.

Variations

• With pasta: Add a small handful of small pasta (ditalini, broken spaghetti) in the last eight minutes of cooking for a more substantial minestrone.
• With kale or chard: Stir in two large handfuls of roughly chopped kale or chard in the last five minutes. They wilt and soften and add considerable color.
• With crispy pancetta: Fry small cubes of pancetta until crisp and scatter over each bowl before adding the pesto. Makes the soup a complete non-vegetarian meal.

See also: White bean toast with garlic and lemon · Rotisserie chicken white bean soup · Lemon orzo vegetable soup · Kitchen journal · Pricing