Preheat oven to 350º. Mix together the wafer crumbs, melted butter and the ground pecans. Press down firmly into the bottom of a springform pan (12 inch)
Using a food processor, mix the cream cheese till smooth. Then add brown sugar and mix till well blended.
Begin adding eggs one at a time, mixing well after each egg. Add the heavy cream. Add the flour, salt, cinnamon and vanilla, blend till smooth. Add pumpkin last and mix until smooth.
Pour filling onto crust. Bake for 1 hour and 15 minutes. You want the cake to be just set. Using a knife loosen the cake from the sides of the pan. (This prevents the cake from splitting at the top)
Allow the cake to cool completely
Blend together the whipped cream and bourbon.
For the chocolate sauce, combine half and half and the butter in a heavy bottom saucepan. Cook over medium heat. You want a thin, paper like skin to appear on the top, but do not boil. Add the vanilla and the chocolate chips and stir till chips are melted and the sauce is completely smooth. Remove from the heat and the let the sauce cool completely.
When cake is cooled completely, remove the sides of the pan and slice the cake. Top each piece with a drizzle of the sauce and top with the bourbon whipped cream