Preheat oven to 300°F/150°C. Place a kitchen towel on the bottom of a large roasting pan or baking dish (to prepare the waterbath). Place 4 6-ounce ramekins, 6 4-ounce ramekins, or 4 shallow fluted dishes on top of the towel.

In a saucepan, heat cream, vanilla pod and seeds on medium heat until steamy. Do not boil. Meanwhile, whisk together eggs and sugar in a medium heatproof bowl until well blended, but not airy. Remove vanilla bean from the hot cream mixture, then pour the mixture slowly and gradually into the egg mixture while simultaneously whisking the egg mixture constantly to prevent curdling. Return mixture to the saucepan and use a spatula to continuously stir the mixture over a low flame until the sugar is dissolved and the mixture has very slightly thickened. Do not boil. Strain the mixture, then pour evenly among the dishes.

Place roasting pan in the oven and pour in boiling water until it reaches halfway up the ramekins. Bake for 25-30 minutes until the custard has set and is just slightly wobbly when gently shaked. Let ramekins cool on a wire rack to room temperature, then chill in the refrigerator for at least 4 hours, preferably longer, and up to 2 days.