Grilled Fish Au Promage

4 x 15(1-175 g/5-6 oz steaks or portions of white
fish, skinned if necessary
salt
freshly ground black pepper
25 g/1 oz polyunsaturated margarine
1 teaspoon dried rosemary
100 g/4 oz finely grated Cheddar cheese, or a
mixture of Gruyere and Parmesan
1 tablespoon (scant) French mustard
2-3 tablespoons plain low-fat yogurt
2 firm tomatoes, sliced
watercress sprigs, to garnish

Wipe the fish with damp kitchen paper towels aid season generously with salt and pepper. Preheat the grill and melt the margarine with half the rosemary in a shallow flameproof dish, large enough to hold the fish in a single layer. Turn the fish in the inched margarine, then grill under a moderate heat for about 4 to 5 minutes (under a low heat for 7 to H minutes, if the fish is still frozen).

Meanwhile, put the cheese, mustard and remaining rosemary into a basin and beat in enough yogurt to make a soft mixture. Turn the fish carefully, spread them evenly with the cheese mixture and continue grilling, very gently, for 5 to 6 minutes. When the surface is golden, but not overbrowncd, arrange 2 slices of tomato on each portion and grill for a further minute.

Serve from the dish, garnished at the last moment with sprigs of watercress.

SERVES 4