Season the shrimp with Creole seasoning, salt, and pepper. Heat a tablespoon of vegetable oil (or peanut oil) in a Dutch oven over medium heat, add the shrimp, saute for a minute or two, and remove from the pan. Set aside.
Add smoked sausage, brown for 3-5 minutes, remove, and set aside with the shrimp.
Add the remaining oil, butter, and flour to the pan, and cook on medium heat, stirring continuously, for 10-15 minutes or until it turns a rich dark brown color (like chocolate). Please don't leave the stove during this process because it burns quickly.
When the roux achieves the desired color, add the onion, garlic, thyme, green pepper, bay leaves, and celery, and cook for 8-10 minutes, stirring frequently.
Follow with 6 cups of stock, bouillon powder, Creole seasoning, and smoked paprika, bring to a boil, and simmer for 15-20 minutes. Add the greens and continue cooking for another 10 minutes. Toss in the shrimp and sausage, and simmer for another 2-3 minutes.
Stir in the gumbo file, green onions, and chopped parsley. Adjust the soup's thickness and flavor with broth and salt.
Serve with a bowl of steaming rice.