01 -
Soak the butter beans in a large bowl with plenty of water overnight.
02 -
Drain the soaked beans and transfer to a large stock pot. Cover with fresh water, bring to a boil, then reduce to a simmer. Skim off any foam that forms on the surface. Cook for 45-60 minutes until beans are tender but still hold their shape.
03 -
Preheat oven to 180°C (350°F). Drain the beans, reserving the cooking liquid. Transfer beans to a large baking dish and add diced tomatoes, onion, celery, garlic, oregano, salt and pepper.
04 -
In a small bowl, whisk together 2 cups of the reserved bean liquid with tomato paste and olive oil until well combined. Pour over the bean mixture, ensuring beans are covered with liquid. Add more reserved liquid if necessary.
05 -
Cover the baking dish with a lid or aluminum foil and bake for 1 hour. Check at 30 minutes to add more liquid if needed. After 1 hour, remove the cover and continue baking for another 30 minutes until the sauce has thickened.
06 -
Allow to cool slightly before serving. Garnish with fresh chopped parsley before serving as a main dish, side, or appetizer.