Open the oysters and remove from their shells to retain the water.
Filter the water which has been retained and pour it into a saucepan.
Simmer the water and delicately poach the oysters for 20 to 30 seconds depending on their size.
Immediately remove them using a colander and let them drain well.
Reserve the cooking liquor.
Rinse the hollow shells under running water and arrange them in a baking dish inside the oven on a bed of rock salt.
Place one oyster inside each shell.
For the zabaglione
Pour 200 ml of oyster cooking liquor into a saucepan.
Add the Noilly Prat and pepper, bring it to the boil, and allow it to reduce for 3 minutes before removing it from the heat.
Place the egg yolks in another pan and whisk them until they become frothy.
Add the mixture by drizzling it into the Noilly saucepan and continue to whisk.
Cook for 3 minutes over a low heat while continuing to whisk, add the fresh cream, whisk for a few more seconds, and then remove it from the heat.
Divide the zabaglione among the oysters
Cook the oysters under the grill and remove them as soon as they are well coloured.
Serve directly from the oven.