Combine cream and coconut milk in a small saucepan and heat just until scalding.
Preheat the oven to 350°F. Line a small 3-inch tall roasting pan with parchment paper.
In a medium bowl whisk together egg yolks, vanilla, and 1/2 cup sugar until pale yellow and thick. Slowly add warm milk mixture, whisking well to combine.
Divide mixture between four 1/2 cup ramekins and place in roasting pan.
Pour boiling water into roasting pan to come halfway up sides of ramekins and carefully place entire pan into the oven. Bake for 30 to 40 minutes or until the custard is almost set but still jiggles in the center.
Remove from oven and carefully lift ramekins of pan, placing on a flat plate or tray. Refrigerate until completely.
Just before serving, sprinkle remaining sugar over the tops of the custards and using a kitchen torch or oven broiler, quickly brown the surfaces. Serve immediately.