- Coarsely shred spinach. oelt first measure of butter in a frying pan, then add garlic and spinach and toss over heat for 2 minutes to wilt. Transfer spinach to a shallow ovenproof dish.
- Melt second measure of butter in a saucepan. Stir in the flour until smooth. Remove from the heat and stir in milk and cream. Return pan to the heat and stir continuously for 3 to 5 minutes, until the mixture thickens.
- Stir in the cheese and season sauce with salt and pepper. Arrange fish portions on the bed of spinach and season with salt and pepper.
- Spoon the cheese sauce over the fish and bake for 25 minutes, until fish is cooked and topping has turned golden brown.