Mackerel with Pistachio Pesto

Mackerel isn’t much celebrated in France - it’s considered a lesser fish and too smelly to cook at home. However, it’s my children’s favourite fish, and mackerel are abundant, cheap and full of goodness, so I cook them quite regularly. They are easy to tackle whole, juicy and flavoursome, and the brain food argument is an added bonus. Imagine getting better marks at school next day thanks to what you had for tea! I’m not great at barbecues, so my fish tends to get roasted in the oven or coo