Crust
1/2 cup fine graham cracker crumbs
1/4 cup granulated sugar
1/2 cup butter, softened

Preheat the oven to 375 degrees F.

Combine graham cracker crumbs, sugar and butter and mix well. Press the mixture firmly into an ungreased 9-inch pie plate. Press flat onto bottom only. Bake for 8 minutes or until the edges are slightly brown. Reduce the oven temperature to 350 degrees F for the filling.

Filling
16 ounces cream cheese
1 cup sour cream
2 tablespoons cornstarch
1 cup granulated sugar
2 tablespoons butter, softened
1 teaspoon vanilla extract

Combine cream cheese, sour cream, cornstarch and sugar in the bowl of a mixer. Mix until the sugar has dissolved. Add the butter and vanilla extract and blend until smooth, being careful not to over-mix or the filling will become too fluffy and will crack when cooling. Pour the filling over the crust. Bake at 350 degrees F for 30 to 35 minutes, or until a knife inserted 1 inch from the edge comes out clean. Cool for 1 hour.

Topping
3/4 cup sour cream
1/4 cup confectioners' sugar

Mix the sour cream and confectioners' sugar. Spread the mixture over the top of the cooled cheesecake. Chill or freeze until ready to eat.