Place red beans in a bowl or pot, cover with water at least 2 inches above. Soak overnight (8+ hours).
Heat olive oil in a Dutch oven over medium heat. Brown sausage slices on both sides. Set aside.
Add butter to the pot. Sauté onion for 3 minutes, then add celery and peppers. Cook 4 minutes. Stir in garlic and cook for 15 seconds.
Mix in salt, oregano, thyme, paprika, cayenne, and black pepper. Cook 1 minute.
Pour in broth, scraping up browned bits. Drain and rinse beans, add to pot with sausage.
Add bay leaves. Bring to a boil, then reduce to low. Cover and simmer 90–120 minutes until beans are tender.
Remove bay leaves. Mash 1 cup of beans and stir back in to thicken.
Add parsley and green onions. Simmer 5 minutes. Serve over cooked rice with extra garnish.