Preheat the oven to 325°F., and spray the two pans with vegetable oil spray.
Drain pumpkin by gently placing the canned pumpkin in an ultra-fine strainer. The liquid will slowly seep through. Be careful that the pumpkin itself does not seep through. If you don't have an ultra-fine strainer, use a coffee filter in a regular strainer, and just let the pumpkin sit for 30-60 minutes in the filter. Discard the liquid.
In the large bowl of an electric mixer, beat the cream cheese until very smooth and soft. Add the sugar and vanilla and beat until well incorporated. Slowly add the eggs, pumpkin, flour, spices, and vanilla. Pour into the two prepared pans, and rotate the pans back and forth against the counter to get rid of trapped air.
Place the pans in the oven in a bain-marie, and bake for for 1.5 hours. A bain-marie is a water bath which provides a more uniform baking temperature than the air of the oven. The reason for using a bain-marie is to prevent cracking of the cheesecake top and to give the cheesecake a smoother texture. For this water bath, use a pan with shorter sides than the sides of the cake pans you are baking using for the cheesecakes. Partially fill the bain-marie with cool water, and place it on the oven rack about 15 minutes before you are ready to bake the cheesecake. The amount of water in the bath should be such that after you put in the cheesecake pan, the water level is nearly at the top of the bain-marie.
Cool to room temperature on a cake rack. Loosen the edges of the cake with a table knife, and invert over a small cake rack. Quickly and gently spread the bottom of the cake with graham cracker crumbs, and invert the cake on a serving platter. Chill for 24 hours before serving. As soon as the cake is firm, cover tightly with plastic wrap. This cake freezes well for about 6 weeks.