Adjust the top rack to be positioned in the middle of the oven.
Finely chop the nuts or add them to a food processor.
Add all the ingredients to a large bowl and stir until well combined.
Press the mixture into a 10 1/2 inch buttered springform pan. Using a measuring cup, press the crust and try to line the sides about to the middle of the pan edges, set aside.
Refrigerate for at least 20 minutes.
Make sure all the ingredients are at room temperature before your begin.
In the bowl of a stand mixer or in a large bowl using a hand mixer beat the cream cheese until light and fluffy on medium-low speed.
Add the sugar a little at a time and continue beating until well combined and creamy.
Add the eggs one at a time, and beat after each addition until well combined.
Mix cornstarch with flour and add to the batter, whisk until fully combined. Careful not to over-mix.
Add vanilla extract.
Add the sour cream and beat well, stopping to scrape the sides and bottom of the bowl.
Pour cheesecake batter into the prepared springform pan.
Read the post for "water bath" tips if you want to bake the cheesecake using a "water bath".
Bake in the preheated oven for one hour and 15 minutes.
Try not to open the door to the oven. At the 60-minute mark check on the cheesecake if it's done. A small area in the center should wobble slightly and the edges should be puffed and light golden brown.
Turn the oven off and prop open the oven door and leave the cake to cool in the oven for one hour.
After one hour, remove from oven and place on a cooling rack for about 2 hours, until the cheesecake is cool enough to be transferred to the refrigerator.
In a medium bowl, whisk together on medium-low speed sour cream and sugar until creamy and fully combined. Taste and add more sugar if needed.
Spread the topping over the cool cheesecake using an offset spatula.
Transfer to the refrigerator and chill for 24 hours.