In a large pot, melt the butter over medium heat.
Once melted and starting to bubble, mix in the flour to make a smooth paste. Cook, stirring constantly, until the roux turns a deep golden brown.
Stir in the celery, onion, and bell pepper.
Continue to cook, stirring occasionally, until the vegetables are completely softened.
Stir in the garlic and tomatoes.
Once the tomatoes start to soften, slowly pour in the seafood stock while continuing to stir.
Stir in the bay leaves, Cajun seasoning, Worcestershire sauce, thyme, and cayenne.
Once the mixture comes to a boil, reduce heat to low, add the shrimp and simmer, stirring often, until the shrimp are cooked through, about 5 minutes.
Stir in the parsley and two of the sliced green onions. Season with salt and Louisiana hot sauce to taste.
Serve hot with rice, topped with the remaining green onion and additional chopped parsley for garnish.