Measure and prepare all ingredients: dice onion, bell pepper, and celery; mince garlic; chop parsley and slice green onions; have crawfish tails thawed and drained; cook 2 cups of rice according to package directions if not already cooked.

Make the roux base

In a heavy-bottomed skillet or Dutch oven over medium heat, add the butter and olive oil. Once butter is melted and starts to foam, add the diced onion, bell pepper, and celery. Sauté, stirring occasionally, until the vegetables are soft and translucent, about 6–8 minutes.

Add garlic and flour

Stir in the minced garlic and cook 30 seconds until fragrant. Sprinkle the flour over the vegetables and stir constantly to combine. Continue cooking and stirring for 4–6 minutes until the mixture turns a light golden tan (this is a blond roux). Do not let it burn; lower heat if necessary.

Build the sauce

Gradually whisk in the chicken stock (about 1/4 cup at a time) to the roux to prevent lumps, bringing the mixture to a smooth sauce. Add the tomato paste and whisk until incorporated.

Season and simmer

Add the Worcestershire sauce, hot sauce, Creole/Cajun seasoning, dried thyme, bay leaf, salt, and black pepper. Bring the mixture to a gentle simmer, reduce heat to low, and cook uncovered for 8–10 minutes, stirring occasionally, until the sauce thickens to a gravy-like consistency.

Finish with crawfish

Stir in the crawfish tails and simmer gently for 3–4 minutes until heated through and flavors meld. Taste and adjust seasoning: add more salt, hot sauce, or Creole seasoning as needed. Remove and discard the bay leaf.

Finish and serve

Stir in the chopped parsley, sliced green onions, and lemon juice. Spoon the étouffée over cooked white rice (about 1 cup rice per serving) and garnish with extra parsley or green onion if desired. Serve immediately.