Mix 1/4 cup KINGSFORD'S Corn Starch, 1/2 cup sugar and 1/4 teaspoon salt in double boiler top. Slowly stir in 1-1/2 cups water. Cook over boiling water, stirring constantly, until thick enough to mound slightly when dropped from spoon. Cover; cook 10 minutes, stirring occasionally. Beat 3 egg yolks and 1/2 cup sugar. Blend a little hot mixture into egg yolks, then stir all into remaining hot mixture. Cook 2 minutes, stirring constantly. Remove from boiling water. Gently stir in 2 tablespoons Mazola Margarine, 1-1/2 teaspoons grated lemon rind and 1/3 cup lemon juice. Cool to room temperature. Turn into baked 9-inch pastry shell. Beat 3 egg whites until foamy. Add 6 tablespoons sugar, 1 tablespoon at a time, beating well after each addition. Continue beating until stiff peaks form when beater is raised. Spread some meringue around edge of filling first touching crust all around; then fill in center. Bake in 350-degree F. oven 15 to 20 minutes or until meringue is lightly browned.