It is best to prepare the sauce the day before:
Put in a pan 0.5L fish stock, 0.25L mussel juice, 5cl dry white wine and 1cl white vinegar.
Reduce over a low heat to around three-quarters of the volume.
Add 40cl cream and let it simmer for 4-5 minutes.
Taste for seasoning and let it cool.
Moisten the sea bass with oil and add pepper.
In the lower part of a steaming pot, put in water and the thyme.Put the sea bass flat in the upper part of the steamer.
Ensure the water is boiling vigorously: the fish will cook in only 5 minutes.
Prepare the base of the sauce. Put 10 soup spoons of the sauce in a pot.
Lightly whisk in 20cl of liquid cream and blend it carefully into the sauce.
Put 3 soup spoons of the sauce on the plate and spread it out.
When the sea bass is ready, put thez caviar on the fish and let it absorb it.
Put the fish on plates and put the plates in the oven for not more than 30 seconds.