1. Combine the mustard, honey, vinegar, garlic and pepper in a large bowl and stir well to combine. Place the beef in a shallow bowl. Measure out 2 tablespoons of mustard mixture and rub all over the beef. Marinate the steak for 30 minutes at room temperature or up to overnight in the refrigerator.
2. With a vegetable peeler, remove a strip of skin from around each potato. Drop the potatoes in a large pan of boiling water and cook until they are just tender, about 20 minutes. Drain the potatoes well. Add to the bowl of mustard glaze, tossing to coat. With a slotted spoon, transfer the potatoes to the broiler. (Leave room in the broiler pan for the onion wedges and beef.)
3. Add the onion to the mustard mixture in the bowl, turning the wedges to coat. Add to the broiler pan with the potatoes.
4. Preheat the broiler. Add the steak to the mustard-glazed potatoes and onion in the pan. Broil 8 cm from the heat for 8 minutes, turning the steak, potatoes and onion midway through cooking. Let the broiled steak stand for 5 minutes before slicing. Serve with watercress.

PER SERVING

311 calories
30 g protein
7 g total fat
3 g saturated fat
66 mg cholesterol
31 g total carbohydrate
7 g sugars
6 g fibre
191 mg sodium

There are two good reasons to serve meat and potatoes on a bed of salad greens: the fresh greens provide a delicious contrast to the meat; and at the same time, they round out the meal with important nutrients, such as carotenoids, vitamin C, folate and fibre.