In a large kettle, sauté onions, green pepper, and garlic in butter or margarine. Blend in flour and cook over low heat until all butter or margarine is absorbed. Remove from heat and add all other ingredients except shrimp, rice, and parsley. Simmer for 45 minutes over medium heat, stirring occasionally.
Just before serving, remove bay leaf, add shrimp, and simmer for 5 minutes or until shrimp turn pink. Serve over bed of rice and sprinkle with parsley.