A highly successful dinner-party starter — not the cheapest of dishes, but quite easy to do and very tasty. You can prepare everything in advance, and then the shells only need 20 minutes in the oven. Serves 6.
You may be dubious about raw fish, but I can assure you that this tastes superb and is a very elegant and original starter (if you can get hold of the fresh tuna of course). It’s very rich — you only need small helpings.