Clean the mussels well - it is best to scrub them under running water with a brush. Throw away opened clams and clams with broken shells.
Melt the butter in a large saucepan and fry the finely chopped onion and the very finely chopped garlic until they just turn translucent. Deglaze with water and wine and add the lemon juice. Then add the bay leaves, lemon peel, celery, thyme and a lot of salt and pepper, bring to the boil and simmer for 5 minutes.
Put the mussels in the pot and cook for about 10 minutes with the pot closed, until they are all open. During this time, shake the pot from time to time.
At the end, throw away the clams that haven`t opened. Fish out the bay leaves, lemon peel and celery and also throw them away. Stir in the crème fraiche and the chopped parsley.
Serve in deep plates - oversized pasta plates are especially nice.
Baguette goes well with it.
This recipe is enough with bread as the main meal for 2 people, but can also serve as a starter for 3-4 people.