Butter a 9" spring form pan generously and wrap with a double layer of aluminum foil. Put the pan on a baking sheet.

Melt 4 tablespoons butter and pour over cookie crumbs. Mix until crumbs are evenly coated with butter. Pour into spring form pan, press with your fingers into an even layer. Put in the freezer while the oven preheats.

With a rack centered in the oven, preheat to 350°. Bake crust (on baking sheet) for 10 minutes. Cool on wire rack while you make the cheesecake.

Reduce the oven temperature to 325°. Start boiling water.

With an electric or stand mixer, on medium speed, in a large bowl beat the cream cheese until fluffy, 4 minutes. With the mixer running add sugar, flour, and salt and beat another 4 minutes. Beat in vanilla. Add eggs one at a time, beating for 1 minute after the addition of each egg. Reduce the mixer to low and beat in the sour cream until well incorporated. Pour about half of the cheesecake batter into the spring form pan.

With electric mixer on low speed beat the pumpkin, cinnamon, and nutmeg into the remaining cheesecake mixture. Pour on top of cheesecake mixture in the spring form pan. Batter will come to the top of the pan.

Put a large roasting pan in the oven, put the cheesecake in the roasting pan (still double wrapped in foil), pour boiling water into roasting pan half way up the spring form pan. Bake for 1 1/2 hours. Turn oven off and leave cheesecake in the oven with the door ajar for 1 hour. (Prop the oven open with a wooden spoon if necessary, mine stays open a little bit by itself.)

Remove cheesecake from the oven and let cool to room temperature on a wire rack. Cover loosely and refrigerate for at least 4 hours, overnight is better.

Carefully run a sharp knife between the edge of the pan and the cheesecake, especially around the crust. Undo the latch and carefully remove the sides of the pan. Set the cheesecake, still on the spring form pan base on a serving platter. Cut, serve, and enjoy!