Season the shrimp evenly with Cajun seasoning and set aside.
1 ½ pounds medium shrimp, 1 tablespoon Cajun seasoning
Heat the vegetable oil in a large skillet or Dutch oven over medium-high heat. Add the shrimp and cook for about 2 minutes, just until pink. Remove shrimp from the pan and set aside.
1 tablespoon vegetable oil
Reduce heat to medium and add the butter to the same pan. Once melted, whisk in the flour. Cook, stirring constantly, for 6 to 8 minutes, until the roux turns a deep peanut-butter color.
⅓ cup butter, ⅓ cup all-purpose flour
Add the onion, bell pepper, celery, thyme, and garlic. Cook for 3 to 4 minutes, stirring often, until the vegetables begin to soften.
1 small onion, ½ cup green bell pepper, 2 celery ribs, ¼ teaspoon dried thyme leaves, 4 garlic cloves
Gradually whisk in the chicken broth, stirring constantly to create a smooth sauce.
3 cups chicken broth
Stir in the diced tomatoes, Worcestershire sauce, and bay leaves. Bring to a gentle boil, then reduce heat and simmer uncovered for about 20 minutes, until slightly thickened. Season with salt and black pepper to taste.
2 cups fresh tomatoes, 3 tablespoons Worcestershire sauce, 2 bay leaves, Salt and black pepper
Stir in the green onions, parsley, lime juice, and the cooked shrimp along with any accumulated juices. Cook for 2 to 3 minutes, just until the shrimp are heated through.
¼ cup green onions, ¼ cup fresh parsley, Juice of ½ lime
Remove bay leaves and serve hot over steamed rice.