Preheat oven to 350°F

Place the crumbs in a mixing bowl and add the butter and sugar. Blend well.

Place the crumb mixture on to the bottom and partly up the sides of a greased springform mold. Smooth the crumb mixture along the bottom to an even thickness.

Bake for 10 minutes in a 350°F oven. Cool before filling.

preheat oven to 400°F.

Beat together cream cheese and sugar until smooth and light.

Beat in eggs, vanilla and cornstarch, only until thoroughly mixed.

Stir in sour cream until the mixture is well blended.

Pour the mixture I to the prepared crust and bake for 45 minutes. Allow the cake to cool in oven, with the door propped slightly open for 3 hours. Chill.