Drain and rinse the beans. Place them in a pot of well-salted water, covered by several inches of the water, and simmer for about 40 minutes to an hour. When done, the beans should be tender but not mushy. Make sure you boil them enough otherwise the beans will be too hard to eat even after baking.
Meanwhile, prepare the sauce. Heat the oil in a large pan over medium heat. Add the onion, carrots, and salt, and cook for about 10 minutes, while stirring occasionally, until the vegetables are tender.
Add the garlic and cook for another minute or two then stir in the tomatoes and oregano.
Once the beans are done, drain them, reserving the cooking water. Transfer the beans to the pan with the tomato sauce and let everything simmer for about 20 minutes. Check the sauce occasionally, if it seems to dry, add a ladle of the reserved cooking water.
The beans are done when the tomato sauce has thickened considerably and the beans are soft and buttery.
Serve with a dollop of vegan sour cream and garnish with parsley.