DO-AHEAD TIP: Cook brown rice.
Heat the oil in a large skillet with a tight-fitting lid over medium heat; add onion, bell pepper, celery and garlic and sauté until tender-crisp.
Gradually stir in flour until smooth.
Stir in next 6 ingredients (tomatoes through bay leaves). Reduce heat, cover and simmer for 20 minutes, stirring occasionally.
Add shrimp and cook for 5 minutes or they turn pink. Remove and discard bay leaves.
Serve over hot cooked rice.