Eric's Best New York Style Cheesecake

Bring all ingredients to room temperature. Place oven shelf in the center of oven and preheat to 375 degrees F (190 degrees C). Wrap the outside of a 9 inch springform pan with foil. Generously butter the inside of the pan.
In a large bowl, beat cream cheese and butter until smooth. Mix in sugar and cornstarch. Blend in sour cream and whipping cream. Add amaretto and vanilla. Stir in eggs and egg yolk one at a time, mixing thoroughly between each addition. Pour batter into prepared pan.
Pour mixture into prepared springform pan. Place pan in another pan at least one inch wider than cake pan and add warm water to the outer pan to create a water bath for the cake (this prevents cracks in your cheesecake). Bake on the center rack of oven for 70 minutes.
Turn oven off and allow to cool with oven door open for one hour. Then remove cake from water bath and chill at least 3 hours before removing from springform pan.