3 sprigs oregano
3 sprigs rosemary
2 bay leaves
2 tablespoons olive oil
4 ounces pancetta (Italian bacon), chopped (optional)
1 onion, chopped
1 leek, white and pale-green parts only, thinly sliced
2 carrots, peeled, chopped
2 celery stalks, chopped
4 garlic cloves, thinly sliced
½ teaspoon crushed red pepper flakes
2 tablespoons tomato paste
1 28-oz. can whole peeled tomatoes, drained
1 Parmesan rind (about 2 ounces; optional)
3 cups cooked cannellini beans, cooking liquid reserved if desired, or two 15-oz. cans, rinsed
Freshly ground black pepper
12 ounces baby Yukon Gold potatoes, scrubbed, cut into ½” pieces
½ bunch Tuscan kale, ribs and stems removed, leaves torn into 1” pieces
2 garlic cloves
1 cup fresh basil leaves
½ cup olive oil
2 tablespoons freshly grated Parmesan
1 teaspoon finely grated lemon zest
Tie oregano, rosemary, and bay leaves together with kitchen twine.
Heat oil in a large heavy pot over medium. Add pancetta, if using, and cook, stirring often, until browned around the edges, about 5 minutes. Add onion, leek, carrots, celery, garlic, and red pepper flakes; season with salt. Cook, stirring often, until onion is translucent and carrots are tender, 10–12 minutes. Add tomato paste and cook, stirring to coat, until slightly darkened, about 3 minutes.
Add tomatoes, crushing with your hands as you go, then herb bundle, Parmesan rind, if using, and 6 cups water or reserved bean cooking liquid, or a combination. Season with salt and pepper and bring to a boil. Add potatoes, reduce heat, and simmer until potatoes are tender and flavors have melded, 20–25 minutes. Add kale and beans; cook until kale is tender, about 5 minutes. Discard Parmesan rind and herb bundle.
Do Ahead: Soup can be made 2 days ahead (or 2 months if frozen). Let cool; transfer to airtight containers and chill.
Pulse garlic and basil in a food processor until finely chopped. Transfer to a small bowl and stir in oil, Parmesan, and lemon zest; season with salt.
Serve soup topped with pistou.