1. Cut and clean the mackerel then cut off the heads

2. Wash the fish and pat them dry on absorbent paper

3. Grease a shallow ovenproof dish with 1 oz of the butter

4. Wash, dry and thinly slice the cucumber

5. At the base of the dish, put a layer of cucumber slices (leave some slices for the top layer)

6. Put the fish on top of the cucumber layer

7. Cover the fish with the remaining cucumber slices

8. Season to taste with freshly ground pepper

9. Sprinkle the wine or vinegar over the fish and the cucumber

10. Cut 1 oz of butter into small knobs and dot the fish and cucumber

11. Cover the dish with a lid or foil

12. Bake in the center of the preheated oven for 30minutes

13. Remove the dish and transfer the fish and cucumber onto a serving dish

14. Strain the juices from the fish through a fine sieve into a saucepan

15. Bring the juices to the boil while adding the remaining butter in bits and stirring occasionally

16. When the liquid has decreased by half, pour it over the fish

17. Serve hot or cold

List of ingredients required:

(serves 4 people)

4 mackerel (about 1/2 lb each)
3 oz butter
Salt and black pepper
1 small cucumber
2 tablespoons white wine vinegar or dry white wine

The oven should be preheated at a temperature of 400F (200C)