Prepare the Pan & Crust: Preheat oven to 355°F (180°C). Lightly butter a 9-inch springform pan. Mix crushed gingersnap cookies, melted butter, and salt. Pack the mixture into the pan, covering the bottom and sides, and bake for 8-10 minutes. Leave the oven on.
Beat Cream Cheese: In a large bowl, beat softened cream cheese until creamy. Scrape down the sides to ensure smooth mixing.
Add Sugar & Vanilla: Mix in sugar, salt, and vanilla, scraping the sides to combine evenly.
Incorporate Eggs: Beat in eggs one at a time, mixing well and scraping the bowl between additions.
Add Eggnog & Nutmeg: Stir eggnog and grated nutmeg into the batter until smooth.
Pour & Prep for Water Bath: Pour the batter into the baked crust. Place the springform pan in a larger pan, then into an even bigger pan for a water bath.
Bake the Cheesecake: Boil water and carefully pour it into the outer pan. Bake for 70-80 minutes until edges are set and the center is jiggly. Turn off the oven and leave the cheesecake inside with the door slightly open for 20 minutes.
Cool & Chill: Let the cheesecake cool to room temperature, then refrigerate for at least 8 hours or overnight.
Make Whipped Cream & Decorate: Whip cream, sugar, and vanilla to stiff peaks. Fold in rum and spread over the chilled cheesecake. Sprinkle with nutmeg and garnish as desired. Enjoy!