Fancy fillet with prunes

Make an incision across the length of each fillet and fold open so it is double in size. Flatten the fillets slightly.
Stuff 10 of the prunes with the almonds or oysters and arrange lengthwise in the centre of one of the fillets. Place the other fillet on top and secure with string. Season with salt and black pepper.
Peel the small onions, leaving them whole (if using big onions, quarter them). Heat the oil in a fairly large saucepan and brown the fillets. Remove from the pan and brown the onions. Remove from the pan and set aside.
Pour the stock and wine into the saucepan, add the rind and bring to the boil. Thicken with the cake flour paste and return the whole onions (do not add the onion quarters yet, if using) and fillets to the saucepan. Cover, reduce the heat and simmer slowly for 30 minutes.
Add the onion quarters and remaining prunes and simmer for 15 minutes. Season with sugar to taste and stir in the cream.
Remove the fillet from the sauce and loosen the string. Slice the fillets and serve with onions, prune sauce and mashed potato.
Serves 4-6.