Wash and drain strawberries. Mash and cook 3/4 of them with the cornstarch and sugar. Cook over very low heat for about 5 minutes until clear and thickened. Let cool completely. Reserve the other 1/4 of them and slice them and set aside
Sprinkle the bottom of a baked pie shell with powdered sugar.
Spread the raw sliced strawberries over the pie shell
Add cooled filling. Place in fridge and cool completely.
Whip heavy cream with powdered sugar until stiff peaks form. Spread whipped cream over the pie filling. Refrigerate until ready to serve