Preheat the Oven: Set your oven to 320°F (160°C). Arrange four ramekins in a deep baking dish.
Prepare the Custard Mixture: In a saucepan over medium heat, bring the heavy cream to a gentle simmer. Add salt, white pepper, and nutmeg, stirring to combine. Remove from heat.
Temper the Egg Yolks: In a separate bowl, whisk the egg yolks until smooth. Gradually pour the warm cream mixture into the egg yolks, whisking continuously to prevent curdling.
Strain and Add Flavorings: Pour the mixture through a fine-mesh sieve into a clean bowl to ensure a smooth custard. Stir in the lemon zest.
Assemble the Ramekins: Evenly distribute the crab meat among the ramekins. Pour the custard mixture over the crab meat, filling each ramekin nearly to the top.
Create a Water Bath: Pour hot water into the baking dish until it reaches halfway up the sides of the ramekins. This bain-marie method ensures even cooking.
Bake: Carefully place the baking dish in the preheated oven. Bake for 35-40 minutes, or until the custards are set but still slightly jiggly in the center.
Cool and Chill: Remove the ramekins from the water bath and let them cool to room temperature. Cover with plastic wrap and refrigerate for at least 3 hours, preferably overnight.
Caramelize the Sugar: Just before serving, sprinkle a thin, even layer of granulated sugar over each custard. Use a kitchen torch to caramelize the sugar until it forms a golden, crispy crust.
Garnish and Serve: Allow the sugar to harden for a minute. Garnish with chopped fresh herbs and serve immediately.