1. Whip the heavy cream with powdered sugar in a large bowl until stiff peaks form. Set aside.

2. In another bowl, beat mascarpone cheese until smooth. Add eggnog, vanilla extract, and nutmeg. Mix until fully combined and creamy.

3. Gently fold the whipped cream into the mascarpone-eggnog mixture. Do not overmix to keep the texture light and fluffy.

4. In a shallow dish, combine the brewed espresso and rum or bourbon if using. Quickly dip each ladyfinger in the coffee mixture—just enough to soak without becoming soggy.

5. Start layering: In each serving cup, place a layer of soaked ladyfingers, followed by a spoonful of the eggnog mascarpone mixture. Repeat the layers until the cup is full.

6. Chill the cups in the refrigerator for at least 3 hours or overnight for best flavor.

7. Before serving, dust the tops with cocoa powder and an extra sprinkle of nutmeg.