The crunchiness of the cucumber and fennel offset the fattiness of the mackerel for a delightful light supper.
I never used to pickle vegetables until we started doing it at the restaurant and I've really taken to it. I love cucumber and fennel in salads for crunch and a sharp kick, and they're ideal for a fatty fish such as mackerel.
50g white wine vinegar
½ tsp chopped fresh chilli
2 baby gem lettuce, sliced
½ head of small fennel sliced
Rind of 1 lemon, grated
25ml groundnut oil
4 mackerel fillets, scored
Make the pickling liquid by heating the sugar and vinegar in a pan on medium, until the sugar has dissolved.
Peel the cucumber, cut lengthways, remove the seeds then slice horizontally.
Place the pieces in a bowl, pour over the pickling liquid and leave to marinate while you prepare the rest of the dish.
Combine the fennel, lettuce and chilli, season lightly and add the lemon rind. Then add the cucumber.
Put the oil in a non-stick pan over a medium heat and, when it's hot, put the mackerel fillets in, skin side down.
Cook the fish for 3-4 minutes until the skin crisps up.
Turn and sear on the flesh side, remove and when cool enough, flake the mackerel over the cucumber salad and serve immediately.
• Angela Hartnett is chef patron at Murano restaurant and consults at the Whitechapel Gallery and Dining Room, London. Twitter.com/angelahartnett
Mackerel with pickled cucumber salad. Photograph: Linda Nylind for the Guardian