This recipe is a keeper. We took many liberties with the Smitten Kitchen recipe (like omitting the cheese and the celery, and using sherry instead of white wine) and it was still delicious for dinner and lunch the next day.
Bring medium pot of salted water to boil. Cook chard, or your preferred hearty green, for one minute, then drain and squeeze out as much extra water as possible. Coarsely chop chard.
Wipe out medium pot to dry it, and heat olive oil over medium. Add carrots, celery, onions and garlic and saute for 15 minutes. Try not to brown them.
Add sherry (scraping up any bits that have stuck to the pot) and cook it until it reduced by three-fourths. Add beans, broth, tomatoes, a few pinches of salt, freshly ground black pepper, thyme and bay leaf and bring to a boil. Reduce heat to medium-low and simmer for 20 minutes.
Add chard and cook for 5 minutes more. Remove thyme and bay leaf. Add more broth if you'd like a thinner stew and adjust salt and pepper to taste. Serve as is, drizzled with sherry vinegar (This step is worth it, make sure you do this).