When buying your mussels, make sure they're heavy and closed or close quickly when touched. If not, they're not fresh!
1 kg fresh mussels
3 tbsp vegetable oil
2 medium onions, peeled and chopped
3 cloves garlic, peeled and chopped
1 14oz can peeled plum tomatoes
two generous pinches saffron threads
2 sprigs fresh thyme
150 ml dry white wine
salt and freshly ground black pepper
150 ml 35% cream
1 tbsp chopped fresh parsley
Scrub the mussels well and remove any beards. Rinse in cold water and place in a saucepan. Place over high heat for 2 - 3 minutes until the shells have just opened. Discard any that do not open. Remove from heat, remove mussels from their shells and reserve. Strain the liquid from the pot into a bowl.
Heat the oil in a deep, heatproof dish and sauté the onions and garlic over medium heat until soft and lightly coloured. Add the tomatoes with their juices, breaking them up slightly. Simmer for 5 minutes.
Add the saffron, thyme and wine and stir to mix well. Stir in the mussel liquor, taste and adjust the seasoning, using salt sparingly.
Five minutes before serving, add the reserved mussels to the soup with the cream. Stir to mix well, then reheat gently without allowing it to boil, until the mussels are heated through. Sprinkle with parsley and serve with crusty French bread.