MELT butter in medium saucepan over medium heat. Add celery, green pepper, onion, and garlic; cook, stirring occasionally, for 5 minutes or until vegetables are tender. Stir in flour. Gradually stir in evaporated milk, water and tomato paste. Cook, stirring constantly, until mixture just comes to a boil. Cook an additional 1 to 2 minutes or until mixture slightly thickens. Stir in shrimp, parsley, seasoning, salt and hot pepper sauce. Cook until heated through.
SERVE over rice.
NOTE:If a spicier dish is desired, substitute Creole seasoning for the OLD BAY Seasoning.