In a medium bowl, beat egg yolks and sugar until light and creamy.
In a medium saucepan, heat the milk, vanilla and spices over medium heat until the mixture starts bubbling slightly, whisking constantly. Set aside and cool for a couple of minutes.
Add a little of the warm milk to the egg yolks and whisk to temper the egg mixture. Add the rest of the milk and blend to combine.
Return this mixture to the pan, add the brandy and stirring constantly heat for about 1 min. until frothy.
Cover and reserve at room temperature until ready to use.
Combine all the ingredients in a small bowl.
Press mixture firmly into the bottom and up the side of a 9-inch springform pan.
Bake for 10 min., then set aside to cool.
Cover the bottom of the pan with aluminum foil to prevent water from leaking into the cake during baking.
Fill a baking pan with about 3/4 inch of hot water. Place it on the middle rack of the oven.
In the bowl of a stand mixer, beat the cream cheese on low speed until light and fluffy.
Add the sugar, flour and nutmeg, and keep beating, scraping the side of the bowl with a rubber spatula.
Add 1 cup of the reserved eggnog and blend thoroughly.
Add eggs, 1 at a time, beating after each just until incorporated.
Pour cream cheese mixture into the prepared crust, and bake at 300°F in the water bath for 1 hour 15 min.
Let the cheesecake cool in the oven with the door closed for 30 min.
Open the oven door and let cool for another 30 min.
Refrigerate without covering for 5 hours or overnight.
Beat the whipping cream, 1/4 cup of the remaining reserved eggnog and powdered sugar in a large bowl until stiff peaks form.
Fill a piping bag with the whipped cream and use to decorate the top of the cheesecake.