Saut� shrimp in butter in large skillet over medium-high heat 2 to 3 minutes; remove and set aside. Add flour to remaining butter in skillet; stir over medium heat until lightly browned. Stir in onions, celery, green peppers, and garlic; cook until they begin to turn transparent. Add stock, tomato sauce, lemon slices, sugar, thyme, basil, bay leaves, salt and cayenne; simmer about 10 minutes. Stir in green onions, parsley, and reserved shrimp; cook 5 minutes longer. Serve over hot rice.
Makes eight servings.