Hang woodcock for 4 to 6 days.
Clean and draw birds, reserving the livers. Truss legs close to the body; tie a piece of bacon around each bird; season generously with salt and freshly ground black pepper, and roast in a fairly hot
Chop carcasses finely; put them in a saucepan with a little olive oil and finely chopped shallots, and simmer until shallots are soft. Add champagne, port and tomato concentrate, and continue cooking for a few minutes. Chop the raw livers; add them, together with the juices in the roasting pan in which the birds were cooked, to the chopped carcasses, and simmer sauce for 1 hour.
Cut bread slices in half; trim crusts and sauté slices in butter until golden. Spread with sieved foie gras. Place them on a heated serving dish. Warm woodcock suprêmes and legs through in a little butter; sprinkle with cognac, and flame.
To serve: arrange woodcock pieces on canapés and rub sauce over birds through a fine sieve. Serve immediately.