1. Heat oil in a large Dutch oven over medium-high heat; gradually whisk in flour, and cook, whisking constantly, 5 to 7 minutes or until flour is chocolate colored. (Do not burn mixture.)
2. Reduce heat to medium. Stir in onion and next 4 ingredients, and cook, stirring constantly, 3 minutes. Gradually stir in chicken broth; add chicken and next 2 ingredients. Increase heat to medium-high, and bring to a boil. Reduce heat to low, and simmer, stirring occasionally, 20 minutes. Add shrimp, and cook 5 minutes or just until shrimp turn pink.
Note: We tested with Zatarain's Creole Seasoning and Savoie's Andouille Sausage.