See parts 1 and 2
  Recipe by: Marcel Desaulniers.
      Place a 9"x1 1/2" cake pan partially filled with 4 cups
  of hot water on the bottom rack of the 300 F oven (the
  bottom rack should be at least 3 inches below the center
  rack).  Place both cheesecakes on the center rack of the
  oven and bake for 1 hour and 10 minutes, until the internal
  temperature of the cheesecake fillings reaches 170 degrees
  F.  Turn off the oven and allow the cheesecakes to remain
  in the oven for an additional 20 minutes.  Remove form the
  oven and cool at room temperature for 20 minutes.
  Refrigerate the chocolate cheesecake for 1hour, but keep
  pumpkin cheesecake at room temperature (do not remove
  either cake from pan.
     To prepare the ganache, heat the heavy cream, butter,
  and sugar in a 2 1/2-quart saucepan over medium-high heat.
  When hot, stir to dissolve sugar.  Bring the mixture to a
  boil.  Place the chocolate in a stainless steel bowl.  Pour
  the boiling cream over the chocolate and allow to stand for
  5 minutes.  Stir until smooth.  Allow to cool to room
  temperature.
     Pour 1 cup of the semi-sweet chocolate ganache over the
  top of the chilled chocolate cheesecake.  Spread evenly
  over the top of the cake.  Invert the pumpkin cheesecake
  onto the layer of ganache.  Gently press down on the cake
  to set in place.  Wrap the entire springform pan with film
  wrap and refrigerate for 3 hours.
     The cheesecake can now be released from the springform.
  Remove film wrap and wrap a damp, hot towel around the
  sides of the pan (the towel should be large enough to
  completely wrap around and cove the sides of the pan) and
  hold around the pan form 1 minute.  Carefully release and
  remove the springform pan.  Using a cake spatula, smooth
  the sides of the cake with 2 to 3 Tbsps. of the ganache.
  Spread the remaining ganache evenlyacross the top of the
  cake.  press remaining cookie/pecan crumbs into the sides
  of the cake, coating evenly.  Refrigerate for at least 30
  minutes before cutting and serving.
     Heat the blade of the serrated slicer under hot water
  before cutting and run it under hot water after making each
  slice.  (In the notes section of the recipe called The
  Chef's Touch, Marcel suggests the following:  For an extra
  special touch, decorate the top of the uncut cake with sour
  cream and brown sugar: whisk together in a stainless steel
  bowl 3/4 cup sour cream and 1 Tbsps. light brown sugar.
  Pour the mixture onto the center area of the cake.  Using a
  spatula, spread the sour cream to within 2 inches of the
  outside edge of the top of the cake.  Now for the final
  touch, evenly space 12 pecan halves 1/2 inch from the outer
  edge of the top.  refrigerate for an hour before cutting
  and serving.)  This is complicated and time-intensive, but
  it is really and truly worth the work and can easily be
  done a little at a time over a few days.  This has been my
  special Thanksgiving and Christmas dessert ever since.
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