Heat the oven to 350°F (175°C). Butter eight small molds and coat them with sugar.
Whisk the yolks, whole egg, sugar, coconut, coconut milk, melted butter, vanilla, and salt until combined. Strain the mixture into a pitcher and rest for 10 minutes.
Bake:
Divide the custard among the molds. Place them in a roasting pan and pour in hot water halfway up the sides.
Bake for 35 to 40 minutes until the tops are set and glossy. Remove from the water bath and cool, then refrigerate for at least 2 hours.
Unmold:
Run a thin knife around each edge, invert onto a plate, and finish with toasted coconut if desired.
Notes
Straining removes any chalaza and keeps the texture smooth.
Avoid boiling the water bath so the custard stays delicate.