Boiled Custard Eggnog

Combine sugar, flour, and salt in a large heavy-bottomed saucepan or double boiler, whisking together until well blended and no lumps remain.

Beat egg yolks in a separate bowl until pale and smooth, then gradually whisk them into the sugar-flour mixture until fully incorporated.

Slowly pour milk into the egg mixture while stirring constantly to prevent lumps from forming and ensure an even custard base.

Place the saucepan over medium heat (or use the upper portion of a double boiler over simmering water) and cook, stirring constantly, until the mixture reaches 160°F (71°C) on a food thermometer or coats the back of a spoon.

Remove from heat and strain the custard through a fine-mesh sieve to remove any cooked egg solids and ensure a smooth texture.

Stir in light cream, vanilla extract, and nutmeg until fully combined.

If using whiskey, add it now and stir well to integrate thoroughly. Whiskey acts as a preservative and adds traditional flavor depth.

Cool the eggnog to room temperature, then refrigerate for at least 2 hours before serving, or until well chilled.

Stir or gently shake the eggnog before serving to ensure even distribution of flavors, and pour into chilled glasses or cups.