1. Place the bowl of your ice cream maker in the freezer if needed. Make sure the heavy cream and eggnog are well chilled in the refrigerator.

2. In a medium saucepan, combine the eggnog and heavy cream. Warm over medium heat until steaming and just beginning to bubble around the edges, but not boiling.

3. In a separate bowl, whisk together the egg yolks, granulated sugar, and salt until the mixture looks slightly thickened and lighter in color.

4. Slowly ladle about 1 cup of the hot eggnog mixture into the yolk mixture while whisking constantly to temper the eggs.

5. Pour the tempered yolk mixture back into the saucepan with the remaining warm eggnog and cream, whisking to combine.

6. Cook over medium-low heat, stirring constantly with a heatproof spatula, until the custard thickens enough to coat the back of the spoon and a line drawn with your finger stays clean. Do not let it boil.

7. Remove the pan from the heat. Stir in the rum or bourbon, vanilla extract, nutmeg, and cinnamon until evenly combined.

8. Pour the custard through a fine-mesh sieve into a clean bowl to remove any tiny bits of cooked egg.

9. Press a piece of plastic wrap directly onto the surface of the custard to prevent a skin from forming, then chill in the refrigerator until very cold, at least 4 hours or overnight.

10. Once chilled, pour the custard into your ice cream maker and churn according to the manufacturer’s directions until it reaches a thick, soft-serve consistency.

11. Transfer the churned ice cream to a freezer-safe container, smoothing the top with a spatula. Sprinkle with a little extra nutmeg if desired.

12. Cover and freeze for 3–4 hours, or until firm enough to scoop. Let sit at room temperature for a few minutes before serving, if needed.