Preheat your oven to 325°F (163°C). Prepare a 9-inch springform pan by greasing it and lining the bottom with parchment paper. In a bowl, combine graham cracker crumbs, melted butter, sugar, and nutmeg until it resembles wet sand. Firmly press this mixture into the bottom of the pan, ensuring an even layer. Bake for 10 minutes until slightly golden, then remove from the oven and let cool.

Lower the oven temperature to 300°F (148°C). In a large mixing bowl, beat the softened cream cheese, granulated sugar, and flour until smooth and creamy. Gradually add in the eggnog and ground nutmeg, mixing thoroughly. Incorporate the eggs one at a time, mixing gently after each addition.

Carefully pour the cheesecake filling over the cooled crust in the springform pan. Use a spatula to smooth the top. Set the pan aside while preparing for the baking.

To create a water bath, place the springform pan into a larger roasting pan and fill the outer pan with warm water until it reaches halfway up the sides of your cheesecake pan. Bake for 1 hour to 1 hour and 40 minutes, or until the center jiggles slightly yet appears set.

When baking is complete, turn off the oven and let the cheesecake rest inside with the door closed for 30 minutes. Then crack the oven door open slightly and allow the cheesecake to cool for an additional 30 minutes. Move the cheesecake to the refrigerator and chill for 5 to 6 hours or overnight.

In a mixing bowl, combine cold heavy cream, eggnog, and powdered sugar. Whip using an electric mixer on medium-high speed until stiff peaks form.

Carefully remove the cheesecake from the springform pan and peel away the parchment paper. Top with the whipped cream and sprinkle extra nutmeg on top.