To Make The Crust:

1. Preheat oven to 375ºF and grease the bottom of a 9-inch springform pan
2. Mix together the cookie crumbs, sugar and melted butter. Press into the bottom of a springform pan, going up the side of the pan no more than 1/4 inch. Bake 8-10 minutes. Remove and let cool. Decrease oven temperature to 325ºF

To Make The Filling:

1. Meanwhile, in a stand mixer, cream the cream cheese and Nutella on medium speed until smooth. Add the sugar and continue mixing until there are no lumps. Add the vanilla extract and heavy cream and stir until combined. Add the melted chocolate and mix together. Add the eggs and yolks one at a time; mix each in before adding the next.
2. Wrap two layers of aluminum foil around the sides of the springform pan so that it is completely sealed. Pour the cheesecake filling into the pan on top of the cooled crust. Bake in a water bath for 60-75 minutes. The outer edges should be set and the center will still jiggle slightly when you move it. (The cake continues cooking after it’s removed from the oven.) Cool for 30 minutes, then remove the springform rim. Cool completely, then place into the refrigerator for at least 8 hours, overnight is best.

To Make The Nutella Ganache:

1. Heat over low heat or a double boiler the Nutella and cream until the mixture has become one. Cool for about 15 minutes (it should be easy to spread but not runny) and spread onto the cooled cheesecake, or use a pastry bag or fork to drizzle the ganache on top.