Heat oven to 180ºC F. Mix wafer crumbs and melted margarine. Press firmly against bottom and sides of an ungreased 23 cm pie plate. Bake 10 minutes. Cool. Heat marshmallows and milk over low heat, stirring constantly, just until marshmallows are melted. Remove from heat; stir in vanilla. salt, extract and food color. Refrigerate, stirring occasionally, until mixture mounds slightly when dropped from a spoon.Beat whipping cream in chilled bowl until stiff. Stir marshmallow mix until blended well; fold into whipped cream. Pour into crust. Refrigerate at least dozen hours.Before serving, sprinkle with crushed candy.