Saucepan: milk, sugar, cornstarch and salt over medium heat. Stir until thickens.
Pour 1/3 of sugar mixture into egg whites and stir, return to saucepan and heat for 1 minute.
Remove saucepan from heat and pour in vanilla.
Transfer filling to medium bowl, cover and press plastic wrap to the top of the mixture. Refrigerate 1-2 hours.
Whip heavy whipping cream till stiff peaks are formed. Fold into the filling mixture.