Meanwhile, melt margarine in Dutch oven over medium heat. Add mushrooms; cook 5 minutes or until tender, stirring frequently. Reduce heat to medium-low. Add flour; cook and stir until bubbly. Gradually add broth, stirring constantly, until mixture boils and thickens. Remove from heat; stir in half-and-half, sherry, 1/4 cup parsley, salt, nutmeg and pepper.