Combine cornstarch & 1/2 c sugar. Slowly add milk to egg yolks, then stir into sugar & cornstarch mixture. Cook in double boiler, stirring constantly, until it coats spoon. Remove from heat, add vanilla. Remove one cup of this custard mixture and stir in chocolate bits until melted. Pour chocolate mixture inyo pastry shell & chill. Soften gelatin in water and add to remaining hot custard; stir until gelatin is dissolved. Add flavoring. Chill until slightly thickened. Beat eggs whites until soft peaks form. Gradually add remaining sugar while beating, until stiff. Fold custard/gelatin into egg whites and pile over chocolate layer in pie shell. Chill until set and garnish with chopped walnuts. Mrs. Henry D. Chaplin