Instructions:
Prepare the Bourbon and Sugar Mixture:
In a saucepan, combine the sugar and bourbon (or whiskey). Heat over medium heat, stirring occasionally until the sugar is mostly dissolved, and the mixture is warm (not boiling).
Remove from heat and allow it to cool completely.
Mix the Egg Yolks:
While the sugar-bourbon mixture is cooling, beat the egg yolks in a separate bowl until they become light and slightly yellow in color.
Once the bourbon-sugar mixture has cooled, slowly and gently whisk in the beaten egg yolks, stirring constantly to prevent the yolks from cooking.
Whip the Heavy Cream:
In a large mixing bowl, whip the heavy cream until stiff peaks form (you can adjust the stiffness based on your texture preference, but keep in mind that the cream should have enough body to give the eggnog a rich, luxurious feel).
Combine the Whipped Cream:
Gently fold the whipped cream into the cooled bourbon-egg mixture. Don't worry if the mixture is a little lumpy at first; it will smooth out as it integrates.
Beat the Egg Whites:
In a clean bowl, beat the egg whites until stiff peaks form, but not so stiff that they are dry.
Carefully fold the beaten egg whites into the rest of the eggnog mixture. Use a gentle folding motion to maintain the lightness and airiness of the eggnog.
Add the Dark Rum:
Stir in the dark rum to the eggnog mixture, mixing gently until fully incorporated. For an extra smooth texture, you can use a hand mixer to combine everything thoroughly.
Chill and Serve:
Transfer the eggnog to a cool place and refrigerate for at least 2 hours before serving. Note that the alcohol may separate and settle at the bottom, but this is perfectly normal.
Before serving, give the eggnog a gentle stir or fold to re-incorporate the alcohol and achieve a smooth consistency.
Optional Garnish:
Serve chilled in glasses with a sprinkle of freshly grated nutmeg or cinnamon on top for that classic holiday touch.