Mussel and Saffron Soup
Melt the butter in a large pan which has a tight fitting lid, add the onion and thyme, and cook for a few moments until fragrant. Add the mussels and wine. Cover the pan with the lid and cook over high heat. After about two minutes lift off the lid, using a large spoon turn the mussels over, bringing the bottom ones to the top. Cover again and cook until they have just opened. The whole process should only take about 4 minutes.
Tip the mussels out in to a colander set over a bowl to catch every drop of liquid. Remove the mussels from the shells as soon as they are cool enough to handle, cover with a damp towel to prevent them drying. Discard the onion and thyme; strain the liquid through a fine cloth to remove any sand.
Add the cup of cream to the cooking liquid along with the saffron and chopped thyme, and bring to a boil.
While the soup is coming to the boil make the liaison by whisking the ½ cup of cream with the yolks.
Add some of the cooked mussels and the julienne to the soup. Pour in the liaison and stir constantly, returning almost to the boiling point, to thicken the soup. Do not allow the soup to boil at this point or the yolks may curdle. Remove from heat, adjust the seasoning and serve.