In a large saucepan, cook shallots and garlic in simmering wine until translucent.
Stir in cream and curry powder. When sauce is heated through, add mussels. Cover, and steam mussels for a few minutes, until their shells open wide. With a slotted spoon, transfer steamed mussels to a bowl, leaving the sauce in the pan. Discard any unopened mussels.
Whisk butter into the cream sauce. Turn heat off, and stir in parsley and spring onions. Serve immediately.