Thaw shrimp, if frozen.
Peel and devein shrimp, leaving tails intact if desired.
Rinse shrimp; pat dry with paper towels.
In a medium skillet, cook flour over medium heat about 6 minutes or until brown, stirring often.
Transfer to a medium bowl; set aside.
In a 4-quart Dutch oven, heat oil over medium heat.
Add onion, sweet pepper, celery, and garlic; cook and stir about 5 minutes or until tender.
Slowly whisk broth into browned flour.
Add broth mixture, water, and Cajun Spice Mix to Dutch oven.
Stir in okra.
Bring to boiling; reduce heat.
Cover and simmer for 15 minutes.
Add shrimp; cook for 2 to 3 minutes or until shrimp is pink.
To Serve: spoon gumbo into 8 bowls and top each serving with rice, a shrimp, and a green onion, if desired.
If desired, pass hot pepper sauce.
Makes 8 (1-1/4 cups gumbo plus 1/3 cup rice) servings.
Cajun Spice Mix: In a small bowl, combine 1/2 tbs dried thyme, crushed; 1/4 tbs ground white pepper; 1/4 tbs salt; 1/4 tbs ground black pepper; and 1/4 tbs crushed red pepper.