In a small skillet, sauté celery and onion in butter until tender. Add the apple, lemon juice and Mrs. Dash® Lemon Pepper Seasoning Blend. Cook, uncovered, over medium-low heat until apple is tender, stirring occasinally. Stir in the cranberries, SugarTwin® and water. Cook and stir until berries pop and liquid is syrupy. Add walnuts.