Bake graham cracker crust in 350° oven for 10 min. Remove to rack to cool.
Prepare lemon pudding according to package directions. Place in refrigerator to cool for 30 min.
In a medium bowl with an electric mixer, beat egg whites until soft peaks from when beaters are raised. Beat in ½ cup of sugar, 2 tablespoons at a time, beating after each addition. Beat until stiff peaks form. Gently fold the egg whites into lemon pudding until just combined.
In a medium bowl, beat ½ cup of heavy cream until stiff. Gently fold into pudding mixture. Mound high in pie shell. Refrigerate for 1-2 hours until firm.
Beat ½ cup heavy cream with confectioners sugar until stiff. Spoon into pastry bag with rosette tip, make a lattice top on pie.