01 - Toss the shrimp with Cajun seasoning in a bowl and set aside until ready to use.
02 - In a large, heavy-bottomed skillet or Dutch oven, melt the butter over medium heat. Add the flour and stir constantly to make a roux. Cook for 5-7 minutes, stirring continuously, until the mixture turns a medium caramel color.
03 - Add the onion, bell pepper, and celery to the roux. Sauté for 5 minutes until vegetables begin to soften.
04 - Stir in the garlic and cook for 1 minute until fragrant, being careful not to burn it.
05 - Add the drained tomatoes, bay leaf, paprika, thyme, black pepper, cayenne, salt, Worcestershire sauce, and hot sauce if using.
06 - Slowly pour in the stock while stirring constantly to prevent lumps. Bring to a simmer and cook, stirring occasionally, for 20 minutes until the sauce has thickened nicely.
07 - Add the seasoned shrimp to the simmering sauce and cook for 5-7 minutes, until the shrimp are pink and just cooked through. Remove from heat immediately.
08 - Discard the bay leaf. Taste the étouffée and adjust seasoning with additional salt or hot sauce as needed.
09 - Ladle the étouffée over warm cooked rice in bowls. Garnish with sliced green onions and chopped parsley.