Preheat the oven to Gas 4, 180ºC, fan160°C. In a heavy sauté pan, melt the butter and sauté the pork tenderloin, turning around to brown on all sides evenly. Cover with foil, transfer to the oven, and cook for 20 minutes, until cooked through. Keep warm.
Place the stock, grape juice and mustard in a saucepan and bring to the boil. Cook until reduced by half then season to taste. Add any cooking juices from the pork along with the grated beetroot and pomegranate molasses, and continue cooking for a further 10 minutes to reduce further. The sauce will also thicken. Finally add the grated apple and heat through.
Slice the pork tenderloin and serve with the sauce poured over it. Sprinkle with fresh dill.
Feasts: Food For Sharing From Central And Eastern Europe, by Silvena Row, published by Mitchell Beazley, £14·99.
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