1. Preheat the oven to 375 degrees F. 

2. For the crust, combine the graham-cracker crumbs, sugar, and butter, and mix well. Use your hands if necessary to combine all ingredients.

3. Press the mixture firmly into an ungreased 9-inch pie plate. Press flat onto the bottom only. Use a cup to keep the crust the same thickness around the bottom of the pan.

4. Bake for 8 minutes, or until the edges are slightly brown. Remove the crust and reduce the oven temperature to 350 degrees F. 

5. For the filling, combine the cream cheese, sour cream, cornstarch, and sugar in the bowl of a mixer. Mix until the sugar has dissolved. 

6. Add the butter and vanilla and blend until smooth. Be careful not to overmix, or the filling will become too fluffy and will crack when cooling. 

7. Pour the filling over the crust 

8. Bake for 30 to 35 minutes, or until a knife inserted 1 inch from the edge comes out clean. 

9. Cool for 1 hour. 

10. For the topping, mix the sour cream and powdered sugar. Spread the mixture over the top of the cooled cheesecake. Chill or freeze until ready to eat. 

Serves 8.

Tidbits: If you decide to freeze this cheesecake, defrost it for about an hour at room temperature before serving. You may also defrost slices in the microwave oven if you're in a hurry. Set the microwave on high and zap as follows: 

1 slice–15 seconds
2 slices–25 seconds
3 slices–40 seconds 

Be sure to refreeze the remaining cheesecake after slicing.