Heat oven to 450°F. Make pie crust as directed on box for One-Crust Baked Shell using 9-inch glass pie pan. Bake 9 to 11 minutes or until light golden brown. Cool completely, about 30 minutes.
Meanwhile, in 2-quart saucepan, mix granulated sugar, cornstarch, salt and water. Stir in 2 cups of the raspberries. Heat to boiling. Boil 1 minute, stirring constantly. Stir in butter. Cool completely, about 30 minutes.
Stir remaining 2 cups raspberries into cooled raspberry mixture. Spoon into cooled baked shell. Refrigerate at least 2 hours before serving.
To serve, in medium bowl with electric mixer, beat whipping cream, powdered sugar and vanilla on high speed until stiff peaks form. Garnish pie or individual servings with whipped cream. Store in refrigerator.