With a vegetable brush, clean the mussels under cold running water. Pull off and discard any beards. Discard any mussels with a broken shell or those that do not close when sharply tapped. Drain well.
In a stainless steel or coated-aluminum wok, heat the oil over medium heat. Add the onions and garlic, and stir-fry until the onion is wilted. Add the curry paste and turmeric, and cook, stirring, for about 1 minute, until aromatic. Add the wine, clam juice, lime leaves, and lemongrass. Bring to a simmer and cook for 5 minutes. Remove the limes leaves and discard.
Add the mussels, cover the wok tightly, and steam over moderate heat for 5 minutes. The mussels will begin to open. Continue cooking until all the mussels have opened; transfer those that opened to a platter and discard any that fail to open. Add the cream and cilantro leaves to the wok, and stir to blend. Pour over the mussels and serve.