Heat margarine in 3 qt. saucepan over low heat until melted. Stir in flour, salt, thyme and pepper. Cook, stirring constantly, until mixture is smooth and bubbly; remove from heat.
Stir in broth and whipping cream; heat to boiling, stirring constantly. Boil 1 minute, then stir in chicken, peas and carrots, and onions.
Heat oven to 425° F. Prepare pastry. Fill bottom crust with mixture and top with top crust. Bake 35-45 minutes, or until golden brown.Servings: