In a saucepan, slowly fry sliced onions and minced garlic in butter without browning.

Add chopped ham and continue to fry, then add diced tomato.

Incorporate minced sorrel (if using), sliced eel, and shelled shrimp, turning them in the mixture until heated through.

Separately, steam the mussels open and remove them from their shells.

Add boiling water to the liquid left in the mussel saucepan to reach 1 1/4 quarts.

Drop the mussels into this liquid and cook for 15 minutes.

Strain the liquid and pour it over the frying fish mixture in the saucepan.

Add bay leaf, pepper, and salt to the saucepan.

Place the saucepan over low heat and simmer for 10 minutes.

Add shucked oysters with their liquor to the saucepan.

Simmer until the oysters crinkle.

Stir in lemon juice.

Serve the chowder, ensuring each serving contains a selection of each fish and seafood.

Discard the cooked mussels.