Pour 1 cup of cold heavy cream into a mixing bowl. Use an electric mixer to beat it on medium speed until stiff peaks form, about 3-5 minutes. Set aside in the fridge.

In a separate bowl, whisk together 4 egg yolks and ½ cup of powdered sugar until pale and well combined, about 2-3 minutes.

Gently fold 1 cup of mascarpone cheese into the egg mixture until smooth and creamy.

Fold the whipped cream into the mascarpone mixture, maintaining airiness.

In a shallow dish, combine 1 cup of hot brewed coffee, ½ cup of rum extract, and 1 cup of eggnog. Stir until well mixed.

Dip each gingerbread cookie into the coffee mixture quickly, then arrange them in a 9x9-inch baking dish.

Spread a layer of mascarpone filling over the cookies. Repeat with remaining ingredients, making 4-5 layers.

Spread the remaining mascarpone mixture on top, dust with cocoa powder and crushed gingerbread cookies for decoration.

Cover the dish with plastic wrap and refrigerate for at least 1.5 hours. For best flavor, chill overnight.