Combine crust ingredients and pat into bottom and sides of pan. Beat cream
cheese thoroughly; add sugar gradually; add eggs in thirds; add vanilla;
pour into prepared pan. Bake at 375 for 25 minutes; remove from oven and
add topping. To prepare topping, whip sour cream; add sugar and vanilla,
and pour over cake. continue baking at 500 for 5 minutes. Important - chill
at LEAST 24 hours.