Place fish open end downward on a chopping board. Press along the backbone with the heel of your hand to loosen the bone.

Turn over and carefully pull out the main bone.

Cut the fillets in half and skin them using a filleting knife, beginning at the tail end and working up to the head end using a sawing motion, with the knife at an angle to the skin.

Layer up the fillets in a deep casserole, placing onion slices, spices, bay leaves and lemon slices between each layer.

Mix lemon juice and sugar together and pour over the fish. Place a sheet of greaseproof paper directly over the top of the fish and cover with the casserole lid. Store in the refrigerator for 24 hours. Remove the fillets and strain the liquid. Mix 60 ml (4 tbsps) of the liquid with the cream and pour over the fillets to serve.

Layer the potatoes in an ovenproof serving dish and sprinkle salt, pepper, and caraway seeds in between each layer and on top. Spoon the oil over the top of the potatoes and bake, uncovered, in a preheated 200°C/400°F/Gas Mark 6 oven for about 30-40 minutes or until golden and cooked through. Serve with the herring. Garnish the dish with chopped parsley and lemon wedges.