Preheat the oven to 325°F (160°C). Place 4 to 6 ramekins into a large baking dish or roasting pan.

Infuse the cream: Heat the heavy cream and vanilla bean in a medium saucepan over medium heat. If using a vanilla bean, split it open, scrape out the seeds, and add both seeds and pod to the cream. Bring to a simmer, remove from heat, and let it steep for 10-15 minutes. If using vanilla extract, add it later.

Whisk the egg yolks: In a separate bowl, whisk together the egg yolks, granulated sugar, and a pinch of salt until smooth and pale.

Temper the eggs: Slowly pour the hot cream into the egg mixture, whisking constantly to prevent curdling. Once combined, return the mixture to the saucepan and cook gently over low heat for 2-3 minutes, stirring constantly. Add vanilla extract at this stage if using.

Strain the custard: Strain the custard through a fine-mesh sieve into a clean bowl to remove the vanilla pod and ensure a silky smooth texture.

Bake in a water bath: Pour the custard evenly into the ramekins. Pour hot water into the baking dish until it reaches halfway up the sides of the ramekins. Bake for 40-45 minutes, or until the custard is set but still slightly wobbly in the center.

Cool and chill: Remove the ramekins from the water bath and allow them to cool to room temperature. Refrigerate for at least 2 hours or up to 2 days.

Caramelize the sugar: Just before serving, sprinkle a thin, even layer of granulated sugar on top of each custard. Using a kitchen torch, caramelize the sugar until golden and crisp. Alternatively, place under a broiler for 1-2 minutes.

Serve and enjoy: Once the sugar has hardened, serve immediately and enjoy the creamy custard with its delightful crispy top.