1. Bring the haddock, milk, and clam juice to a boil in a frying pan over medium heat. Reduce the heat to low, cover, and simmer for 6–8 minutes, or until the fish is opaque.

2. Meanwhile, put the spinach in a medium saucepan. Cover and cook over medium-low heat for 3 minutes, or until wilted. Season with salt, pepper, and the nutmeg. Spread the spinach in a buttered shallow ovenproof dish. Arrange the fish over the spinach, leaving the cooking liquid in the pan. Cover with aluminum foil to keep the fish warm.

3. Melt the butter over low heat. Whisk in the flour and let bubble for 1 minute without browning. Whisk in the poaching liquid and bring to a boil over medium heat, whisking often. Stir in the Cheddar until melted, then season with salt and pepper. Pour the sauce over the fish and spinach. Mix the bread crumbs, Parmesan, and parsley together and sprinkle over the sauce.

4. Position a broiler rack about 6in (15cm) from the heat and preheat the broiler. Broil about 2 minutes, or until the topping is golden brown. Serve immediately.

Variation:

Smoked Salmon Mornay: The dish can be made using hot smoked salmon instead, but season carefully as the fish is already salted.