Step 1: Make the Roux : In a large heavy-bottomed pot or Dutch oven, combine vegetable oil and flour over medium heat. Stir constantly with a wooden spoon until the roux turns dark brown (like chocolate), about 15–20 minutes. Patience is key—this develops the rich gumbo flavor.
Step 2: Sauté the Vegetables : Add onion, bell pepper, and celery to the roux. Cook for 5–7 minutes until softened. Stir in garlic, smoked paprika, thyme, oregano, cayenne, black pepper, and salt. Cook another 1–2 minutes to release the aromas.
Step 3: Build the Broth : Slowly pour in seafood stock while whisking to prevent lumps. Add diced tomatoes (if using), bay leaves, and Worcestershire sauce. Bring to a simmer.
Step 4: Add Okra and Fish : Stir in sliced okra and fish fillets (if using). Simmer uncovered for 15–20 minutes until okra is tender.
Step 5: Add Shrimp and Crab : Reduce heat to low. Add shrimp and crab meat, gently stirring to combine. Cook for 5–7 minutes until shrimp are pink and opaque.
Step 6: Finish with Herbs : Stir in green onions and parsley. Adjust seasoning with salt, pepper, and hot sauce as desired. Remove bay leaves.