Peel, devein and rinse the shrimp. Pat dry and sprinkle with some Creole seasoning and set aside.
Cut the gumbo crabs in half (head to toe) and sprinkle some creole seasonings over them and set aside.
Chop the trinity and place it in one prep bowl. Chop the garlic, the green onions and the parsley and place them in individual prep bowls. Place the freshly chopped or frozen okra into a prep bowl. Mix together the Herb and Spice Blend and set aside. Measure the stock, vegetable oil and AP flour.
Place the seafood stock in a large stockpot and set the heat to low.
Place a cast iron dutch oven over medium heat.
Add the oil and allow it to become very hot.
Sprinkle the AP flour into the oil and whisk constantly to make a smooth dark roux. About 10 minutes
Remove the Dutch oven from the heat and add the trinity (yellow onions, bell peppers and celery) to the roux and stir to combine. Once combined, return the Dutch oven to medium heat and stir regualrly until it starts to caramelize about 15 minutes.
Add the okra and saute another 5 minutes.
Add the garlic and about half of the Herb and Spice Blend, mix well until you can smell the garlic, about 3 minutes,
Add the green onions and saute another 5 minutes.
While that is simmering, bring the stock to a heavy boil in the stockpot.
Remove the Dutch oven from the heat.
Using a slotted spoon, desolve the roux mixture into the rapidly boiling stock, one spoonful at a time. Stir each spoonful until it is fully incorporated into the stock before repeating the process.
When all of the roux-mixture has been incorporated into the stock, reduce the heat slightly to maintain a steady, low boil for about 10 minutes.
Lower the heat to a low simmer. Cover the stockpot and maintain a low simmer for about 1 hour, stirring occasionally.
Remove the cover and add the gumbo crabs and stir well. Replace the cover and simmer another 15 minutes.
Increase the heat to a medium boil. Add the oysters with their juice, the lump crab meat and the shrimp. These should all be added by hand, a little at a time allowing the gumbo to return to a boil between additions.
Once all the seafood has been added, continue to simmer for about 15 minutes.
Remove the gumbo from the heat. Serve with cooked white rice.