To make caramel melt sugar alone in a small heavy pot, over a low heat. Swirl the pot constantly until the sugar becomes golden. Stir in hot water carefully as the mixture will splatter. Quickly stir to dissolve any lumps and boil for about 2 minutes until liquid is clear.
Pour caramel into a 4 cup soufflé dish which has been lightly greased with butter or margarine. Tilt the dish to ensure caramel coats the base.
To make custard, beat eggs and vanilla in a large bowl. Combine coconut milk and milk with sugar in a saucepan and cook over low heat until sugar dissolves. Remove from stove and beat quickly into eggs and vanilla so eggs do not curdle. Sieve custard only if it is lumpy. Pour slowly on top of caramel in soufflé dish.
Preheat oven to 160°C. in the base of a large roasting pan, place 2 layers of paper toweling, then place the soufflé dish on top before pouring hot water into the roasting pan until halfway up the soufflé dish. Bake in the centre of the oven for about 50 minutes or until a knife inserted into custard is clean when removed. Do not allow water to boil. Remove soufflé dish. Cool in a pan of cold water. Refrigerate, covered with plastic wrap, preferably overnight.
