Doesn’t that mackerel look astonishing? It was such a beautiful lilac pink that it seemed a shame to cook it but, well, needs must when the stomach grumbles. I saw this recipe on the Guardian’s site at the weekend and the thing that interested me about it was the use of sorrel in the pesto. You’re thinking in a Clouseau-esque way but, ha, Louise, you have made ze typo: zer is no zorrel in your title. And you’d be right in one respect and wrong in another.

I did make the pesto with sorrel as per the recipe but I have not made it an essential part of this dish because, well, I couldn’t really taste it. Sorrel to me is the most sharp and citrussy of herbs, it makes a brilliant bedfellow for fish as I said last month and, since it’s not easy to find I think it’s a bit of a waste to use it for this when its very character is lost. So, although grilled courgettes tossed with pesto and lemon juice served with mackerel and rocket is delicious, I don’t think it matters if the pesto used is made with some other herb or leaf. I think a homemade rocket or watercress pesto, thinned with a few extra squeezes of lemon (or even lime) juice would be just as good and a lot less difficult to source. Or just use good old pesto alla Genovese. After all it’s the contrast that matters: oily fish with slightly crispy yet soft courgettes with some herbs and lemon juice made into a sauce. Who knows, you might even get some sun to go with it this weekend…though sadly, right now, that seems about as likely as finding sorrel in a supermarket.

For two you will need:
Cupboard (or things you may already have)
sea salt and black pepper
olive oil, about 2 tablespoons

Shopping list
courgettes, 2 medium (about 350g)
mackerel fillets, 2 large or four small
rocket, small handful (about ¼ of one of those 50g bags)
ready-made pesto, a couple of tablespoons (if you want the sorrel pesto recipe you can find it here)
lemon, 1

How to
1. Rinse the rocket leaves and wipe the surface of the courgettes if necessary.
2. Top and tail the courgettes and cut them on the diagonal into 1cm-thick slices. Put them in a bowl with a tablespoon of olive oil, season and stir so that all the slices are coated.
3. Zest (use it in a salad dressing, for this, or sprinkle it over the mackerel and rocket at the end) and juice the lemon.
4. Run a hand over the fleshy side of the fish fillets and pull out any remaining bones.
5. Place a frying or griddle pan over a medium heat, add the courgette slices and grill on each side for a few minutes until soft. The Ottolenghi recipe doesn’t mention anything about whether they should colour or not but mine did so don’t be surprised if that happens.
6. When the courgettes are soft (and, in my case, golden brown too) put them in a bowl with a tablespoon of pesto and mix together well. Mix the other tablespoon of pesto with a tablespoon of lemon juice to make a thick sauce.
7. Put a little bit of oil onto the mackerel’s skin (not too much; it’s already pretty oily) and put skin-side down in the same griddle/frying pan and cook for about three minutes until the skin is crispy before turning.
8. Whilst the fish is cooking, divide the courgettes between two plates and top with a handful of rocket.
9. Once both sides of the mackerel are cooked, pour the rest of the lemon juice over it, then place on top of the rocket. Drizzle with the pesto-lemon juice mix, add a bit more rocket and serve.