To prepare the Meat:
- Brown the Scotch fillet on all sides in a dash of oil in a hot frying pan. Transfer to a chopping board.
- Mix together the horseradish cream, mustard and brown sugar and spread this mixture on the top and sides of the meat. Place on a foil-lined baking tray.
- Place in 220°C oven and then turn down immediately to 200°C and roast for 40 minutes.
- Set aside to rest for 10 minutes before carving and serving with Mushroom sauce, Roast Potatoes and freshly steamed vegetables.
To prepare the Mushroom Sauce:
- Cook the onion in a dash of oil in a saucepan over a moderate heat for about 5 minutes until softened. Add the garlic and cook for a further minute.
- Stir in the port or sherry and simmer until reduced by half. Add the beef stock, chopped mushrooms and mushroom sauce. Simmer for 10 minutes.
To prepare the Potatoes:
- Peel the potatoes and place in boiling salted water. Bring to the boil and boil for 5 minutes. Drain and return to the saucepan. Shake the potatoes over the heat to rough up the outside edges. Alternatively, use a fork to score the outside of the potatoes, so that the edges are rough.
- Roll the potatoes in the oil so that they are evenly coated and place on a baking tray.
- Cook at 200°C for 15-20 minutes until golden.