Preheat the oven to 325°F/170°C/gas 3.

Whisk together all the ingredients in a ceramic or stainless steel mixing bowl. Divide the mixture among six 1-cup/225ml ovenproof ramekins. Place the ramekins in a baking pan and fill the pan with warm water up to 1 inch/2.5 cm from the tops of the ramekins.

Place the pan in the oven and bake until the custards are set but still a bit loose in the middle, about 35 to 40 minutes.

Remove the pan from the oven, remove the ramekins from the pan, and let the custard cool to room temperature. Cover each with plastic wrap, transfer to the refrigerator, and refrigerate for at least 3 hours or up to 24 hours.

When ready to serve, preheat the broiler.

Remove the plastic covering from each ramekin. Sprinkle a layer of superfine sugar over the surface of each one. Set the ramekins in a baking pan and fill with ice water almost to the tops of the ramekins. Place the pan under the broiler and bake until the sugar crystallizes, about 30 seconds. If you have a small propane torch, you can also caramelize the sugar using the torch.

Remove the ramekins from the pan, dry them off, and serve immediately.