Heat the olive oil in an 8-quart soup pot or stockpot over medium-high heat. Add the onion, celery, bell pepper, 1 teaspoon of the salt, and 1/4 teaspoon of the black pepper and cook, stirring, until the vegetables are tender, about 6 minutes. Add the garlic, dried Italian herbs, and crushed red pepper and cook, stirring, until fragrant, about 1 minute. Add the stock, beans, Parmesan rind, bay leaf, and water and bring to a low boil. Reduce the heat to simmer gently and cook, partially covered and stirring occasionally, until the beans are tender, 45 to 60 minutes.

Using a slotted spoon, transfer about 1 cup of the beans from the pot to a small bowl and mash them with the back of a spoon. Return the mashed beans to the soup and add the remaining 1 tablespoon salt. Bring to a simmer over medium-high heat and continue to cook, uncovered, until the broth thickens slightly, about 15 minutes. Add the remaining black pepper, the broccoli rabe, and rosemary sprig and continue to cook until the broccoli rabe is just tender, about 5 minutes. Stir in the lemon zest and lemon juice. Remove the Parmesan rind, bay leaf, and rosemary sprig and discard them. Serve the soup in wide, shallow bowls, garnished with grated Parmesan and a drizzle of extra-virgin olive oil.