Mackerel, blood orange, chorizo and walnut salad

Method

1. Put a frying pan over a medium-high heat and fry the chorizo for 6 minutes or until crisp. Remove with a slotted spoon onto kitchen paper. Meanwhile, slice off the peel and pith from the oranges (or regular ones), then cut out the segments.
2. Discard some fat from the pan, then fry the red onions for 7 minutes until soft. Add to the kitchen paper. In a bowl, toss the onions and chorizo with the rocket. Fry the mackerel fillets, skin-side down, for 3-4 minutes until crisp, then turn over and fry for 2 minutes more.
3. Mix the Dijon mustard, a pinch of sugar and red wine vinegar, then whisk in the extra-virgin olive oil and chopped walnuts. Toss through the salad, then serve on 4 plates. Break the mackerel into large flakes and scatter on top.