Heavily grease a springform pan.
Combine graham cracker crumbs, butter snd 3 tablespoons of sugar. Mix well.
Press mixture onto bottom and up sides of prepared pan.
Place in freezer while preparing filling.
In a large bowl, beat cream cheese with mixer until fluffy.
Add remaining sugar, cornstarch and vanilla. Beat until combined.
Add eggs one at a time, beating to incorporate.
Add sour cream and stir until blended.
Preheat oven to 325.
Pour filling into crust.
Place the cheesecake pan into a large, deep pan.
Fill the pan halfway up with hot water. This is your water bath and will help ensure your cheesecake comes out crack free.
Bake for 75 minutes, until center is nearly set.
Remove springform pan from bath and place on wire rack.
Allow to cool 15 minutes before releasing spring form.
Allow to finish cooling before refrigerating for at least 3 hours.