In a medium saucepan, pour in the eggnog and add the granulated sugar, ground nutmeg, and salt. Set the heat to medium and gently stir the mixture until the sugar is completely dissolved, taking care not to let it boil.
In a small bowl, combine the cornstarch with 1/4 cup of the warm eggnog mixture, whisking until smooth. Gradually incorporate this slurry back into the saucepan with the remaining eggnog mixture.
Keep whisking the mixture over medium heat until it thickens and begins to gently boil, which should take about 5-7 minutes. Once thickened, remove the saucepan from the heat.
In a separate mixing bowl, whip the heavy cream with the vanilla extract using an electric mixer until soft peaks form.
Once your eggnog mixture has thickened, carefully fold in half of the whipped cream to lighten the pudding. Gently fold in the remaining whipped cream until the mixture is smooth and combined.
To assemble, take a glass dish or individual serving cups and begin layering. Start with a layer of vanilla wafers, followed by a layer of sliced bananas, and then a generous layer of the eggnog pudding. Repeat these layers until all ingredients are used, ensuring the final layer is the pudding.
Cover the assembled dessert with plastic wrap and refrigerate for at least 3 hours to let the flavors meld and for the pudding to set perfectly.
Right before serving, add a dollop of whipped cream on top of each serving and finish with a light sprinkle of ground nutmeg for an extra touch of flavor.
Notes
For an elegant touch, serve in clear glass cups to showcase the beautiful layers.