Put the pot on the stove, turn the heat to medium, and add the oil. When the oil is hot, add the onion, celery, carrots, garlic, herbs, and crushed red pepper (if using) and cook, stirring frequently, until the vegetables are tender, 10 to 15 minutes.
Add the beans, tomatoes, and 6 cups of the chicken broth. Raise the heat to high and bring just to a boil (you’ll know it’s boiling because you’ll see little bubbles breaking at the surface). Lower the heat to low and cook, partially covered (with the lid balanced halfway across the pot), for 40 minutes.
Carefully transfer about 2 cups of the solids to the blender and blend until smooth, then return the blended soup to the pot. Or, use the potato masher and mash some of the soup right in the pot.
Add the pasta and kale and cook, stirring occasionally, until the pasta is tender, about 20 minutes. It should be thick, but is it too thick for you? If so, add 1 more cup of chicken broth and check again. Still too thick? Add another cup of chicken broth. Now taste the soup. Does it need a pinch of salt? If so, add it and then taste again. Serve right away, with lemon wedges and grated cheese, or let cool, transfer to an airtight container, and refrigerate up to 3 days.