Make the custard by mixing together the coconut milk, sugar or honey, eggs, salt and vanilla extract and setting aside until the sugar has dissolved. (You can do this a few hours in advance or overnight to make sure all the sugar dissolves completely.)
Half-fill a wok or a steamer pan with water, cover, and bring to a rolling boil over a high heat.
Meanwhile, strain the custard through a sieve into a jug. Pour into individual bowls or ramekins until each is three-quarters full (or use a shallow baking dish that fits inside the steamer).
Place the custard bowls inside the steamer basket or rack. Cover, reduce the heat to medium and cook for 10–15 minutes (increase the cooking time if using a baking dish). Serve at room temperature or chilled.