This Tuscan white bean soup with kale simmers cannellini beans with a slow-cooked soffritto, garlic, rosemary and a Parmesan rind, then finishes with ribbons of lacinato kale and a squeeze of lemon. Blending part of the pot gives it a creamy body without cream. It takes about 55 minutes, and most of that is hands-off simmering.
Which kale works best in Tuscan white bean soup?
Lacinato kale (also sold as Tuscan kale, cavolo nero or dinosaur kale) has flat, pebbled leaves that soften in about 5 minutes and still hold their shape in the pot. Curly kale works too, but it needs 7 to 8 minutes, and its frilly edges can feel a bit stringy in a spoonful of broth.
Strip the leaves off the woody center stems by pinching the base of each stem and pulling upward. Stack the leaves, roll them loosely like a cigar, and slice them into 1/2 inch (1 cm) ribbons. The stems can go in with the carrots if you slice them very thin, or you can save them for stock.
Spinach and Swiss chard are fine swaps. Spinach wilts in about a minute, so stir it in off the heat. Chard needs about 4 minutes. Whatever green you use, add it at the end so it stays bright and doesn't turn to mush when you reheat leftovers.
What does a Parmesan rind add to the pot?
A Parmesan rind is the hard outer crust left over once you've grated a wedge down to nothing. Dropped into simmering broth, it slowly softens and releases savory, nutty flavor, the same compounds that make aged cheese taste so rich. The soup won't taste cheesy. It just tastes deeper, the way a long-simmered stock does.
Add the rind with the broth and fish it out before serving; by then it'll be soft and chewy. Keep a bag of rinds in the freezer for exactly this, and drop them into the pot straight from frozen.
No rind? Stir 1/4 cup (25 g) of finely grated Parmesan into the pot at the end, or finish each bowl with a spoonful. For a fully vegetarian soup, check the label, because traditional Parmigiano Reggiano is made with animal rennet. A teaspoon of white miso whisked into a ladle of hot broth gives a similar savory lift with no cheese at all.
Canned vs dried cannellini beans: which should you use?
Canned beans make this a weeknight soup. Dried beans turn it into a weekend project with a slightly better payoff: creamier centers, beans that hold their shape, and a cooking liquid you can use in place of some of the broth.
| Bean choice | Amount for this recipe | Extra time | Result |
|---|---|---|---|
| Canned cannellini | 2 cans (15 oz each), drained and rinsed | None | Soft, reliable, mild |
| Dried cannellini | 1 1/2 cups (about 280 g) dry | Overnight soak, then 60 to 90 minutes of simmering | Creamier beans, richer broth |
| Great Northern beans | Same as cannellini | None if canned | A little smaller and firmer |
If you cook dried beans, salt the water once they start to soften and save 2 cups of the liquid. Rinse canned beans well, since the canning liquid can taste tinny and make the broth gluey.
Why part of the pot goes into the blender
Beans carry their own thickener. Their starch sits just under the skin, and once you break some of them open it seeps into the broth and turns it silky. You don't need flour, cream or a roux.
There are three easy ways to get there:
- Blender: ladle 2 cups of soup (beans and vegetables, not just broth) into a blender, vent the lid, and purée until smooth. Stir it back in. This gives the most even, velvety body.
- Potato masher: press it into the simmering pot 8 to 10 times. It's quicker and leaves a rustic, uneven texture.
- Immersion blender: pulse 3 or 4 times right in the pot. Stop early, because it's easy to overshoot and end up with bean purée.
Whichever you choose, do it before the kale goes in. Blended kale turns the whole pot a murky green, and the soup looks far better with dark ribbons of leaf against a pale, creamy broth.
Storing a soup that keeps thickening
Ladle the soup into warm bowls, add a thread of your best olive oil and some grated Parmesan, and serve it with thick slices of toasted sourdough for dunking. It's hearty enough for dinner on its own. Smaller bowls also make a good first course before lemon herb roast chicken.
The soup thickens as it sits because the beans keep drinking up liquid. When you reheat it, add broth or water a splash at a time until it loosens, then taste for salt again. Cool leftovers quickly: USDA leftovers guidance says to refrigerate cooked food within 2 hours and eat it within 3 to 4 days.
For the freezer, hold back the kale if you can and add fresh greens when you reheat. Frozen soup keeps its quality for about 3 months.
The recipe
Tuscan White Bean Soup with Kale, Rosemary and Parmesan Rind
Ingredients
- 3 tablespoons extra-virgin olive oil, plus more for serving
- 1 medium yellow onion, diced
- 2 medium carrots, diced
- 2 celery ribs, diced
- 4 garlic cloves, thinly sliced
- 1 sprig fresh rosemary (or 1/2 teaspoon dried)
- 1/4 teaspoon red pepper flakes
- 1 tablespoon tomato paste
- 2 cans (15 oz / 425 g each) cannellini beans, drained and rinsed
- 6 cups (1.4 L) vegetable or chicken broth
- 1 Parmesan rind, about 2 inches (5 cm) (optional)
- 1 bunch lacinato kale (about 8 oz / 225 g), stems removed, leaves sliced into ribbons
- 1 tablespoon fresh lemon juice
- 1 teaspoon kosher salt, plus more to taste
- Freshly ground black pepper
- Grated Parmesan, for serving
Instructions
- Build the base. Heat the olive oil in a large Dutch oven over medium heat. Add the onion, carrots, celery and a pinch of salt, and cook, stirring now and then, for 8 to 10 minutes, until soft and the onion is translucent.
- Bloom the aromatics. Add the garlic, rosemary and red pepper flakes and cook for 1 minute, until fragrant. Stir in the tomato paste and cook 1 to 2 minutes more, until it darkens to a brick red.
- Simmer the beans. Add the beans, broth, Parmesan rind and 1 teaspoon salt. Bring to a boil, then lower the heat and simmer gently, uncovered, for 20 minutes.
- Thicken the soup. Remove the rosemary stem and the Parmesan rind. Blend 2 cups of the soup until smooth and stir it back into the pot, or mash the beans in the pot 8 to 10 times with a potato masher.
- Add the kale. Stir in the kale and simmer for 5 to 7 minutes, until the leaves are tender and deep green.
- Season and serve. Stir in the lemon juice, then season with salt and pepper. Ladle into bowls and finish with a drizzle of olive oil and grated Parmesan.
Cook's notes
- Make ahead: the soup tastes even better the next day. Add a splash of broth when reheating because it thickens in the fridge.
- Swap the kale for 5 oz (140 g) baby spinach, stirred in off the heat, or Swiss chard simmered for 4 minutes.
- For a vegan version, use vegetable broth, skip the rind and Parmesan, and whisk 1 teaspoon white miso into the finished soup.
Tuscan White Bean Soup questions
How long does this soup take in a slow cooker?
About 6 hours on low or 3 hours on high. Cook the onion, carrot, celery and garlic on the stove first for the best flavor, then move everything except the kale and lemon into the slow cooker. Stir in the kale for the last 20 minutes, then add the lemon juice and season with salt.
How do I freeze bean soup so the kale doesn't go slimy?
Freeze the soup before adding the greens, in airtight containers with about an inch of headspace, and it keeps well for about 3 months. Kale frozen in the broth turns soft and dull after thawing. Thaw the base overnight in the fridge, reheat it with a splash of broth, and stir in fresh kale for the last 5 minutes.
What can I use instead of cannellini beans?
Great Northern beans are the closest swap, a little smaller with the same mild flavor. Navy beans are softer and break down more, which makes a thicker soup. Chickpeas hold their shape and taste nuttier. Butter beans are larger and very creamy. Use the same amount, two 15 ounce cans, drained and rinsed well.
How do I add meat to white bean soup?
Brown 4 ounces (115 g) of diced pancetta or 8 ounces (225 g) of crumbled Italian sausage in the pot before the vegetables, then lift it out and cook the soffritto in the rendered fat. Return the meat with the broth so it simmers along with the beans. Sausage should be cooked through with no pink left before you serve it.
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