Blanch the tomatoes, skin and deseed. Cut the flesh into strips about 5 mm/¼ inch wide and set aside. Skin and fillet the sole. Lightly butter an ovenproof pan large enough to take the fillets without overlapping. Slightly flatten each fillet with the side of a heavy knife or cutlet bat (this will prevent the fillets from curling as they cook), then fold each fillet in two lengthwise. Lay them in the pan and add the fish stock and dry sherry. Cover with buttered paper or foil and poach in the oven for about 3-4 minutes. Remove the fillets, cover and keep in a warm place.
For the sauce, place the liquor over a high heat and reduce until syrupy. Add the cream and continue boiling for 1-2 minutes until slightly thickened, and then add the chives.