Combine milk, 1 cup of the heavy cream, grated nutmeg, cinnamon, lightly bruised cloves, and a pinch of salt in a pot. Heat over medium heat until the mixture is steamy and fragrant—this should take about 5-7 minutes—then remove from heat, cover, and let steep for 30 minutes to allow the spices to fully infuse. This resting period is crucial for developing the authentic eggnog flavor. After steeping, strain the mixture through a fine-mesh strainer to remove the cloves and any spice solids, discarding the solids.

While the milk mixture steeps, set up an ice bath by placing a large bowl over another bowl filled with ice water. Position a fine-mesh strainer over the top bowl and set aside. In your pot with the strained milk mixture from Step 1, add the sugar and stir constantly over low heat for 2-3 minutes until the sugar is completely dissolved. This prevents grittiness in your final ice cream.

In a medium bowl, whisk the room-temperature egg yolks until they're pale and slightly thickened, about 1 minute. Slowly pour half of the warm sugar-milk mixture from Step 2 into the yolks while whisking constantly—this tempering process gradually raises the egg temperature without scrambling them. Once combined, pour the tempered yolk mixture back into the pot with the remaining milk mixture, whisking to incorporate smoothly.

Place the pot over medium heat and stir constantly for about 10 minutes until the mixture thickens enough to coat the back of a spoon—when you run your finger across the spoon, it should leave a clear trail. The mixture should reach about 160-170°F if you're using a thermometer, which ensures food safety while keeping the custard silky. I like to use a wooden spoon for this step because it helps me gauge the thickness better by feel.

Immediately pour the hot custard through the strainer sitting over the chilled bowl with the remaining 1 cup of cold heavy cream from your ice bath setup (Step 2). The cold cream will stop the cooking process instantly and help chill the mixture. Let the bowl sit in the ice bath for about 10-15 minutes, stirring occasionally, until the custard is completely cooled. This rapid chilling prevents any cooked eggy flavors from developing.

Transfer the cooled custard mixture to the refrigerator and chill for at least 4 hours or preferably overnight—this resting period allows the flavors to meld and mellows the egg taste. Just before churning, stir in the vanilla extract and rum if using. For the most authentic eggnog flavor, I don't skip the rum even in small amounts, as it rounds out the spice profile beautifully.

Pour the chilled custard mixture into your ice cream maker and churn according to the manufacturer's instructions, typically 20-30 minutes, until the mixture reaches a soft-serve consistency. Transfer the churned ice cream to a freezer-safe container and freeze for at least 4-6 hours until firm. The ice cream is now ready to scoop and serve.