In a large pot, combine flour and vegetable oil over medium heat.
Stir continuously until the mixture turns a deep brown color for around 20 to 30 minutes.
This mixture is your roux.
Add chopped celery, onion, green pepper, and garlic to the roux.
Cook the vegetables until they are soft and translucent, about 5 minutes.
Add sliced Andouille sausage to the pot and let it cook for an additional 10 minutes.
This part ensures the sausage blends well with the flavors.
Stir in the cooked okra, tomatoes, and chicken stock.
Bring the ingredients to a slow simmer, allowing them to meld together for about 45 minutes.
Finally, add shrimp and crab meat.
Season with salt, black pepper, and cayenne pepper.
Let it cook for another 10 minutes, until the shrimp is cooked through.