Combine maple syrup and mustard; stir well, and set aside. Coat a large nonstick skillet with cooking spray; add margarine, and place over medium heat until margarine melts. Add parsnip and next 3 ingredients; cover, reduce heat to medium-low, and cook 12 minutes or until tender, stirring occasionally. Add syrup mixture; cook, uncovered, over medium-high heat 1 minute or until lightly glazed, stirring constantly. Remove from heat; sprinkle with parsley.