Separate the 6 eggs yolks and whites separated, placing the yolks in a medium heatproof mixing bowl and the whites in a large, clean mixing bowl. Set the whites aside at room temperature.

Whisk the 6 eggs yolks and whites separated yolks with ½ cup of granulated sugar until the mixture turns pale yellow and slightly thickened, about 2 minutes.

In a medium saucepan over medium heat, combine the 2 cups whole milk and 1 cup of heavy cream. Heat until steaming and just beginning to simmer around the edges — do not boil. Remove from heat.

Temper the 6 eggs yolks and whites separated: very slowly pour about ½ cup of the hot 2 cups whole milk mixture into the 6 eggs yolks and whites separated yolk mixture in a thin, steady stream, whisking constantly. This gradually raises the temperature of the eggs yolks and whites separated without scrambling them.

Pour the tempered 6 eggs yolks and whites separated mixture back into the saucepan with the remaining whole milk mixture, whisking to combine. Return to medium-low heat and cook, stirring constantly with a wooden spoon or spatula, until the custard thickens enough to coat the back of a spoon and reaches 160°F on an meat thermometer, about 5–7 minutes. Do not let it boil.

Remove from heat and stir in the 1 tsp pure vanilla extract, ½ tsp ground nutmeg freshly grated preferred, ¼ tsp ground cinnamon, and 1 pinch kosher salt. If desired, stir in the 4 oz bourbon / 4 oz dark rum / 4 oz brandy now. Pour the custard through a sieve into a large mixing bowl or pitcher (Large) to remove any cooked 6 eggs yolks and whites separated bits.

Press a sheet of plastic wrap directly onto the surface of the custard to prevent a skin from forming. Refrigerate until thoroughly chilled, at least 2 hours or up to overnight.

Once the custard is fully chilled, beat the reserved 6 eggs yolks and whites separated whites with a hand mixer or stand mixer on medium speed until foamy. Gradually add the remaining ¼ cup of granulated sugar and continue beating until soft, glossy peaks form.

Gently fold the whipped 6 eggs yolks and whites separated whites into the chilled custard base using a spatula, using wide, sweeping motions until just incorporated. This gives the eggnog its signature light, airy body.

In a separate mixing bowl, beat the 1 cup heavy cream cold with the 1 tbsp powdered sugar until soft peaks form.

Ladle or pour the eggnog into glasses or a punch mixing bowl. Top each serving with a dollop of whipped 1 cup heavy cream and a fresh grating of ground nutmeg freshly grated preferred. Serve immediately and enjoy!