Remove tough stems from silverbeet and finely chop. Coarsely chop leaves.
Heat oil in a large non-stick frying pan over medium heat. Add onion, carrot, oregano and bay leaf. Sauté until onion and carrot are very soft, about 8 minutes. Add garlic. Sauté for 30 seconds.
Add the silverbeet and stock to the pan. Cook, stirring occasionally, until silverbeet begins to wilt, about 2 minutes. Stir in beans. Simmer, covered, 10 minutes. Uncover and cook until silverbeet is tender, 5 minutes. Season with salt and pepper. Remove bay leaf. Sprinkle with parmesan.
Instead of cannellini beans, you can use another type of white bean or, for a nutty flavour, try making this dish with chickpeas. Vary the herbs, too. Fresh thyme, parsley or chervil all work well.