1. Soak the dry red beans in a large bowl covered with about 2 inches of water for at least 8 hours or overnight in the refrigerator.
2. Heat olive oil in a large Dutch oven over medium heat. Cook sliced sausage until browned on both sides, then remove and set aside.
3. Melt butter in the pot, then add diced onions, cooking until softened.
4. Add celery and both bell peppers, cooking for an additional 4 minutes. Stir in garlic and cook briefly.
5. Season the vegetables with salt, oregano, thyme, smoked paprika, cayenne, and black pepper. Cook for another minute before adding the broth, making sure to scrape the browned bits from the bottom.
6. Drain and rinse the soaked beans, then add them to the pot along with the sausage and bay leaves. Bring to a boil, then reduce heat, cover, and simmer for 1 1/2 to 2 hours, or until beans are tender.
7. Remove and discard bay leaves. For a creamier consistency, mash some of the beans against the pot’s side before stirring them back into the mixture. Adjust seasonings as needed.
8. Stir in chopped parsley and green onions and cook for an additional 5 minutes.
9. Serve the hot bean and sausage mixture over cooked rice, garnishing with extra parsley and green onions if desired.