Step 1: Place the heavy cream in a large chilled metal bowl (or the mixing bowl of your stand mixer). Chilling is important because it helps stabilize the cream. Beat the cream with an electric mixer or by hand with a whisk to “soft peaks,” 4 to 6 minutes. Don’t overbeat—the cream should not be stiff or curdled. Transfer to the punchbowl and refrigerate.
Step 2: Place the egg yolks, 1 cup sugar, cinnamon, and cloves in the mixing bowl where you beat the cream. Beat with an electric mixer or by hand with a whisk until the mixture is pale yellow and as thick as marshmallow fluff, 5 to 10 minutes. Slowly beat in the Scotch whisky, mezcal, rum, and vanilla extract, followed by the milk. Pour this mixture into the punchbowl and fold to mix with a rubber spatula. The eggnog can be prepared up to 3 hours ahead—indeed, preparing it in advance helps blend the flavors.
Step 3: Ten minutes before serving, cover the punchbowl with plastic wrap. Load your handheld smoker with hardwood sawdust and direct smoke under the plastic wrap to fill the bowl. Let infuse for 4 minutes. Lift the plastic wrap and gently stir the smoke into the eggnog with a rubber spatula. Repeat once or twice more, or until the eggnog has a pleasant smoky flavor.
Step 4: Using a nutmeg grater or Microplane, grate a dusting of nutmeg over the top of the eggnog. Use a ladle for serving. If you’ve never tasted smoked, made-from-scratch eggnog, you’re in for a revelation.