Bake the 9-inch pie crust according to package or recipe instructions until golden brown. Allow to cool completely.
Wash and hull the fresh strawberries. Arrange them snugly inside the cooled pie crust.
In a medium saucepan, whisk together the granulated sugar, cornstarch, and water. Cook over medium heat, stirring constantly, until the mixture comes to a boil and thickens into a clear syrup (about 2-3 minutes).
Remove the saucepan from the heat and whisk in the strawberry gelatin powder until completely dissolved. Let the glaze cool for 15 minutes.
Pour the cooled glaze evenly over the arranged strawberries in the pie crust, ensuring all berries are well coated.
Refrigerate the pie for at least 4 hours, or until the glaze is completely set.
Just before serving, whip the heavy cream, milk, and powdered sugar in a bowl until stiff peaks form. Spread or pipe over the chilled pie.