In a large pot, make a roux by heating vegetable oil over medium heat and whisking in flour. Cook until the mixture turns dark brown, about 15-20 minutes.

Add chopped onions, bell pepper, celery, and garlic to the roux. Cook for about 5 minutes until vegetables are softened.

Stir in seafood stock, diced tomatoes, Cajun seasoning, thyme, oregano, and bay leaves. Bring to a boil.

Reduce heat to low, and let simmer for 30 minutes, stirring occasionally.

Add shrimp, crab meat, smoked sausage, and okra (if using). Cook for an additional 10-15 minutes until shrimp are pink and cooked through.

Remove bay leaves and adjust seasoning with salt and black pepper as needed.

Serve hot over cooked white rice.