1 Wash and open the oysters. (Hold the oysters rounded side down in a kitchen cloth. Insert the point of an oyster knife next to the hinge and twist to open the shell. Catch the juices and loosen the oyster from the shell and its muscle).
2 Pass the oyster juices through a fine sieve and retain. Put the oysters on one side.
3 Sweat the diced shallot in butter until transparent, add the wine and port and boil to reduce slightly.
4 Then add the oyster liquid, the cream and double cream and quickly boil down until reduced by half. Season to taste with salt and pepper.
5 Turn down the heat, add the oysters, and simmer for about 1 minute. Turn the oysters and simmer for a further 30 seconds.
6 Lift out the oysters with a fork, place in the rounded shells and serve on plates filled with a little sauce and garnished with snipped chives.