1) Preheat the oven to 350°F (180°C). Roast the hazelnuts on a baking sheet for 5 to 7 minutes, until golden and fragrant. Place them in a dry kitchen towel and rub them together to remove their skins. Let the hazelnuts cool and then chop them coarsely. Reduce the oven temperature to 300°F (150°C).

2) In a medium saucepan, heat the coconut milk, the vanilla bean, and its seeds over medium heat. Bring to a low simmer.

3) Meanwhile, in a medium bowl, whisk together the egg, egg yolks, coconut palm sugar, and hazelnut butter until almost lump-free.

4) When the coconut milk has come to a simmer, remove the pan from the heat. Remove the vanilla bean pod and add the milk and bittersweet chocolates. Stir to melt the chocolates into the milk.

5) Pour a little bit of the hot coconut milk mixture over the eggs while whisking to keep the eggs from coagulating. Add the rest of the mixture and whisk. Strain the mixture through a fi ne-mesh sieve into a clean bowl. Add the fleur de sel and stir.

6) Pour the custard into 6 (4-ounce) oven-safe ramekins or jars. Place the ramekins in a deep baking pan and place the pan on the oven rack. Add enough hot water to the pan to come halfway up the sides of the ramekins, creating a water bath.

7) Bake the custard for 30 to 40 minutes or until the center is set. Let the ramekins cool to room temperature. They can be served at room temperature or chilled.