Maquereaux à la Façon de Quimper

I found this recipe in Le poisson en Bretagne, published in 1949 by the Syndicat d’Initiative de Cornouaille. It is now a family favourite.

‘Have mackerel which are very fresh and of a good size. Gut them and cook them in a strongly-seasoned court-bouillon. Once they are cooked, take them out of the water, let them coo