Trim any fat and tissue from the pork fillet, then cut into 1-cm slices.
Quarter, core and slice the apples, and trim and chop the spring onions. Put both aside.
Melt half the butter in a large frying pan, add the pork fillet slices and fry over high heat for 1 minute on each side, or until the meat is very lightly browned. Remove from the pan and keep warm.
Heat the remaining butter in the pan, add the spring onions and cook for 1–2 minutes, until softened. Stir in the flour, add the stock and bring to the boil, stirring.
Strip the leaves from the thyme, then add to the pan with the apples, mustard, and salt and pepper to taste. Cook over moderate heat for a further 4 minutes.
Stir the cream into the sauce, then simmer gently for 2 minutes. Pour in the Calvados or brandy, increase the heat slightly and cook gently for a further 2 minutes. Transfer onto four heated plates and serve immediately.
Tender baby peas cooked with shredded lettuce (as photographed), and a bowl of smooth Chestnut and Celeriac Purée (page 260), make good accompaniments to this dish.
If you prefer, apple juice can be used instead of the alcohol.
NUTRIENTS PER SERVING:
good source of vitamins A, B group and E, and selenium and zinc.