01 - Season the raw shrimp with 1 teaspoon of Cajun seasoning; set aside for later use.
02 - In a large, heavy-bottomed skillet or Dutch oven, melt 4 tablespoons of unsalted butter over medium heat. Gradually whisk in 1/4 cup of all-purpose flour. Continue to cook, stirring constantly, until the roux achieves a deep golden brown color, which typically takes about 5 to 7 minutes.
03 - Incorporate the finely chopped onion, green bell pepper, and celery into the prepared roux. Sauté these vegetables for 4 to 5 minutes until they have softened.
04 - Stir in the minced garlic and cook for an additional 1 minute until fragrant.
05 - Add the drained diced tomatoes, paprika, cayenne pepper, dried thyme, bay leaf, and hot sauce (if desired) to the skillet. Mix all ingredients thoroughly to combine.
06 - Gradually pour in the 2 cups of seafood or chicken stock while continuously stirring to prevent lumps. Bring the mixture to a gentle simmer and cook, uncovered, for 10 to 12 minutes, stirring occasionally, until the sauce has thickened to your desired consistency.
07 - Add the seasoned shrimp to the simmering sauce. Continue to simmer gently for 4 to 5 minutes, or until the shrimp turn pink and are just cooked through.
08 - Taste the étouffée and adjust the salt, black pepper, and heat as needed. Carefully remove and discard the bay leaf.
09 - Ladle the spicy shrimp étouffée over hot cooked white rice. Garnish with sliced green onions and chopped fresh parsley before serving.