Heat 1 tablespoon olive oil in a medium pot over medium-high heat. Add the onion, celery and 1 1/2 teaspoons salt and cook until the vegetables are golden brown, about 5 minutes. Add the beans and broth, bring to a simmer and cook 15 minutes.
Meanwhile, heat the remaining 3 tablespoons olive oil in a large skillet over medium heat. Add the roasted peppers, minced garlic and cilantro and cook until the garlic is soft, about 2 minutes. Stir in the chard, cover and cook until wilted, 1 to 2 minutes. Scrape the contents of the skillet into the pot and simmer until heated through, about 5 minutes. Season with salt and pepper.
Toast the bread, then rub with the whole garlic clove. Serve the soup with the bread and lemon wedges, if desired.
Photographs by Antonis Achilleos
Recipe courtesy of Food Network Magazine