1. Prepare the Vanilla Bean: Split the vanilla bean lengthwise with a paring knife and scrape out the seeds using the back of the knife. Reserve the seeds for the custard and the pod for infusing the cream. If using vanilla extract, measure 1-2 teaspoons.
2. Whisk the Yolks and Sugar: In a medium bowl, whisk together egg yolks and granulated sugar until the mixture becomes pale yellow and creamy. Add the vanilla seeds and bourbon, whisking until fully incorporated.
3. Heat the Cream: Warm the heavy cream (or coconut milk for a dairy-free option) in a saucepan over medium heat, adding the vanilla pod. Heat until it steams and small bubbles form around the edges. Do not boil. Remove from heat and let it steep for 5 minutes.
4. Temper the Eggs: Gradually whisk a small amount of the warm cream into the egg yolk mixture to temper it. Slowly add the rest of the cream while whisking continuously. Strain the mixture through a fine-mesh sieve to remove any curdled egg or vanilla pod remnants.
5. Pour into Ramekins: Arrange 2-4 ramekins in a deep baking dish. Evenly pour the custard into each ramekin, tapping them lightly to release any air bubbles for a smoother texture.
6. Water Bath Baking: Pour hot water into the baking dish, filling it halfway up the sides of the ramekins. Bake at 325°F (160°C) for 30-50 minutes, until the centers are set but still have a slight wobble.
7. Cool and Chill: Carefully remove the ramekins from the water bath and allow them to cool at room temperature. Cover with plastic wrap and refrigerate for at least 4 hours or up to 4 days to set the custard fully.
8. Caramelize the Sugar: Just before serving, sprinkle 2-4 teaspoons of turbinado sugar evenly over each custard. Use a kitchen torch to melt and caramelize the sugar by moving the flame in a circular motion. Alternatively, place the ramekins under an oven broiler for 1-2 minutes.
9. Garnish and Serve: Allow the caramelized sugar to cool and harden for a few minutes. Serve immediately. Optionally, garnish with whipped cream, fresh berries, or a decorative touch for an elegant presentation.