Add the egg nog, heavy cream, sugar, salt and nutmeg to a medium saucepan over medium heat, stirring occasionally, until the mixture just starts to simmer on the edges.
½ cup granulated sugar, 1 cup eggnog, 1 cup heavy whipping cream, ⅛ teaspoon kosher salt, ¼ teaspoon ground nutmeg
Preheat the oven to 325℉/163℃ and add the empty ramekins to a 13×9” casserole dish.
Separate 4 eggs, reserving the whites for another time.
Vigorously whisk the egg yolks in a medium sized bowl for about 1 minute. The mixture will become a bit lighter in color and slightly airy.
4 large egg yolks
Once the cream comes to a simmer, drizzle in one ladle full of cream to the egg mixture while whisking. Do the same with a second ladle, then transfer the egg mixture into the pot with the cream. Whisk immediately until combined then add the vanilla and whisk again. Ladle the mixture evenly between the ramekins.
2 teaspoons vanilla paste or extract
Boil a small pot of water and pour it into the pan in between the ramekins. Fill the pan halfway with water and transfer the pan to the preheated oven. Take care not to slosh water into the ramekins. You could also add the pan to the oven rack, then add the water and gently push the rack in.
Bake for 20-30 minutes. The custard will still feel rather sloshy and jiggly, but will be slightly set on the edges. If using, a digital thermometer should read between 160-170℉.
Remove from the oven, and very carefully transfer the ramekins to a wire rack to cool using tongs and a dish towel. Keeping them in the water will cause the custard to overcook. Cool for 30 minutes, then transfer to the fridge for at least 4 hours, or overnight (uncovered).
When ready to serve, add a spoonful of sugar to the top of one ramekin, rotate the ramekin to spread evenly, then dump the excess sugar to the next ramekin and repeat. Use a kitchen torch to brûlée the sugar until caramelized. Then, sprinkle on a thin layer of sugar with your fingers and brûlée again. This double method creates the best crust and crack.
⅓ cup granulated sugar
Serve immediately.