Clean, peel and chop the soup greens. Peel and slice the onions. Make a brew from the wine, onions, garlic, soup greens and the juice of the lemon and cook in a large saucepan for 10 minutes.
Add the washed mussels to the stock and cook for 5 minutes. Drain the stock and cook in a smaller saucepan for another 5 minutes. Remove the brew from the oven. Add the cream and season with salt, pepper and nutmeg. Add the cream sauce back to the mussels and serve with the baguette.