Method

Peel the cucumber, cut in half lengthwise and scrape out the seeds with a spoon. Using a sharp knife, cut it into long, thin spaghetti-like strips. Place a small mound in the middle of two serving bowls and sprinkle with tarragon. Remove the oysters from the half-shell and place in a shallow pan. Pour in the wine and bring to the boil. Just as the wine starts bubbling, quickly remove the oysters with a slotted spoon, placing five in each bowl around the cucumber. Leave the wine on the heat bubbling away until it has reduced by half. Add the cream and bring to the boil. Remove from heat, season to taste, and use a hand-held blender to whiz the sauce until it becomes light and frothy (about 15 seconds). Spoon the creamy sauce over the oysters and cucumber. Serve warm.