Melt the butter in a large Dutch oven set over medium heat. Add the flour and stir continuously to make a roux. Stir the roux over medium heat until the color of peanut butter, 5 to 7 minutes. (See Tip 4)
Add the onions, bell pepper, celery, and garlic to the roux; cook, stirring occasionally, for 10 minutes. (See Tip 5)
Add the tomatoes along with the salt and Creole seasoning. Cook the tomatoes for 2 to 3 minutes and then whisk in the chicken stock.
Bring the mixture to a boil stirring constantly until thickened. Reduce heat to low; simmer the Étouffée uncovered, stirring occasionally, for 45 minutes or until the vegetables are tender. Can be made in advance up to this point.
Heat Étouffée over medium heat; add the shrimp, stirring to evenly distribute. Cook the shrimp for 5 to 7 minutes, or until they are cooked through. Add the chopped parsley and stir to combine.
Serve immediately over cooked white rice; garnish with minced parsley or sliced green onion tops. Yield: 4 to 6 servings. (See Tip 6)