Place the prepared fish in a greased fireproof dish and grill quickly for 2–3 min. on one side. Meanwhile soften the fat and cream the cheese and the fat together, then work in the milk if used and season to taste. Turn the fish over and spread the cheese mixture over the uncooked side and return to the grill. Reduce the heat slightly and cook gently for a further 10–12 min. until the coating is brown and the fish cooked through. Serve at once.
The topping can be varied: