Cook the potatoes in boiling salted water for 5 minutes. Add the onion and cook for a further 5 minutes or until the potatoes are tender. Drain and return to the saucepan. Off the heat, stir in the mustard, butter and parsley. Season the lamb steaks. Heat a small frying pan until hot and brown them on both sides. Transfer the steaks to an ovenproof dish. De-glaze the pan with the chicken stock to remove the sticky bits and stir in the redcurrent jelly. Allow it to reduce a little then pour it over the lamb. Top with the potatoes and cook in a preheated oven 190?C, 375F, gas mark 5 for 25-30 minutes or until the lamb is cooked through and the potatoes are golden. Serve accompanied with freshly cooked green vegetables or a green salad. NOTES : This recipe is made using our New Zealand Lamb Leg Steaks which contain less than 10% fat. The New Zealand Way Fern Leaf Brand is awarded only to those companies whose products meet the highest standards of excellence and is your assurance of outstanding quality.