Method

1. For the salad of celeriac and anchovies: peel and thinly slice the celeriac into matchsticks, using a Japanese mandolin.

2. In a bowl, combine the celeriac, anchovy, dill, radish and cucumber.

3. Stir in the cider vinegar and add olive oil to taste. Season with salt and freshly ground black pepper, cover the bowl and put in the fridge for 2 hours, to allow the flavours to develop.

4. For the coriander pesto: blend the coriander, peanuts and parmesan to a fine paste in a blender. With the motor running, slowly add the oil until the mixture develops the consistency of thick double cream. Season with a little salt and freshly ground black pepper. Transfer to a bowl, cover and set aside until needed.

5. For the mackerel and potatoes: bring a large saucepan of salted water to the boil and cook the new potatoes for about 20 minutes until just tender. Drain the potatoes, allow them to cool and slice thickly.

6. Heat a knob of butter and a little olive oil in a hot pan and fry the potato slices until golden and crisp on both sides.

7. Season the mackerel fillets with salt and pepper. Heat another knob of butter and a little olive oil in a hot pan and fry the mackerel, flesh side down, for 1 minute, then momentarily flick onto the skin side and pour in the lemon juice. Remove from pan immediately.

8. To serve, arrange a sliced vine tomato in a circle in the middle of a large white plate, spoon on some of the sautéed new potatoes and some of the celeriac salad, put a mackerel fillet on top and garnish with a sprig of watercress. Spoon a little pesto around the outside.