Preheat the oven to 180 °C/350F/gas 4.

Wash and scrub the potatoes. If new they should not need peeling. With a melon baller, scoop out a hollow in each potato large enough to hold an oyster and remove a very thin slice from the bottom to allow it to stand flat. Put the hollowed-out potatoes in a pan of salted water, bring to the boil and boil briskly until just cooked. Drain.

Brush the potatoes inside and out with melted butter, season lightly, put a little horseradish in each and stand them on an oiled baking tray. Put an oyster into each potato. Place in the top half of the oven and bake for 8-10 minutes. Serve immediately with lemon wedges and freshly- ground black pepper.

Try this with lightly-steamed mussels removed from their shells or prawns and mushrooms.