In a heavy-bottomed pot or cast iron dutch oven, melt the butter and cook over low heat until it foams. Add the flour and cook, stirring until the roux reaches a nice golden brown color. At this point season your roux with the seasonings (cajun, salt, pepper, thyme). Next add in the onions, celery, green bell pepper and minced garlic. Cook in the roux for 5 minutes, or until they vegetables start to soften. Whisk in the stock, diced tomatoes, lemon juice, hot sauce, bay leaf, and Worcestershire sauce; turn the heat up to high and bring to a simmer.
Reduce heat to low and simmer uncovered for 25 minutes. Stir in the crawfish and green onions and simmer for 5 minutes. Serve with rice.
Recipe by Kitchen Belleicious at https://kitchenbelleicious.com/2014/01/21/the-best-crawfish-etouffee-ever/