Waterzooi
This name for this Belgian fish stew comes from the Flemish word "water" and the old verb "zooien," meaning "to cook."

1. melt 25 g (5 tsp.) butter in a cocotte or Dutch oven; add the onion and cook for a few minutes; 
2. add the mussels and a few celery leaves; add the white wine; cover and place over high heat until the mussels open; drain and shell the mussels; filter the cooking liquid; 
3. melt 50 g (3 tbsp.) butter; add the finely chopped carrots, leeks and celery; add a ladleful of the cooking liquid from the mussels; cover and cook over medium heat for 10 minutes; 
4. place the fish, boned and cut into large pieces, on top of the vegetables; season with salt and pepper; add the remaining cooking liquid from the mussels; cover and place into a preheated 180° C (350° F) oven for 15 minutes. 

1. place the fish into a tureen or deep dish; 
2. add the cream, chervil and mussels to the liquid in the Dutch oven; 
3. pour the mixture over the fish; serve very hot.