Meanwhile, stem and clean the red chard leaves in 2 changes of water. Rinse the stems and dice. Set aside. Cut the leaves in ribbons, or coarsely chop, and set aside.
03Heat the olive oil in a heavy nonstick skillet over medium heat and add the onion and chard stems. Cook, stirring often, until tender, about 5 minutes. Add the garlic and continue to cook, stirring, until the garlic is fragrant, about 1 minute. Add the potatoes and stir together, then transfer to pot with the beans. Bring back to a simmer, cover and simmer 30 minutes, or until the potatoes and beans are tender. Taste and adjust salt.
04Add the chard and thyme leaves to the pot, cover and simmer for 15 minutes. The chard should be very tender. Stir in freshly ground pepper to taste and the parsley. Taste, adjust seasonings and serve, passing the Parmesan to sprinkle on the top.