Boil the sugar and water in a wide-bottomed pan without stirring. Reduce the heat and simmer, swirling the pan occasionally until a light brown caramel has formed. Remove the pan from the heat. Add the lime juice, holding the pan lid over at a slight angle for protection. Cover and continue to simmer the caramel until it has dissolved. Remove the lid, reduce a little until the caramel turns syrupy, pour into the prepared ramekins.
Bring the coconut milk, milk and lemongrass to the boil in a pan. Remove the pan from the heat, leave to infuse for approx. 15 mins. Thoroughly mix the eggs and sugar, pour the milk into the eggs while stirring, pour into the ramekins through a sieve.
Cook in a bain-marie:
cover each ramekin with foil, place on a clean cloth in an ovenproof dish.
Pour in boiling water to 2/3 the height of the ramekins. Bake for approx. 30 mins. in the lower half of an oven preheated to 170°C. Take out of the oven, remove the foil. Leave the puddings to cool, then refrigerate for approx. 4 hrs. Carefully slide the tip of a knife around the edges of the caramel puddings. Briefly dip the ramekins in hot water and turn out onto plates.