Mackerel and beetroot are abundant at this time of year and this is wonderful light supper. The ingredients list seems long but it is quite simple to make as most of them are a marinade. And of course both beetroot and mackerel have beneficial health qualities. I eat beetroot every day and try to eat mackerel at least 3-4 times per week, mostly smoked for lunch in a salad.

The cardamom makes it especially delicious – even my friend who normally does not eat mackerel came back for the second fillet. I served it with courgettes steamed with oregano and marjoram. You could also serve with spinach or kale. 

Serves 4

4 tbsp olive oil
2 garlic cloves, peeled and crushed
5cm piece fresh ginger, peeled and finely grated
Finely grated zest of 1 lemon, plus 2 tsp lemon juice
15 cardamom pods, bashed, seeds removed and roughly ground, outer pods discarded
8 mackerel fillets, skin on and pin-boned
80g plain flour
Salt and freshly ground black pepper
30g unsalted butter
5g picked coriander leaves, to serve

For the beetroot
3 medium beetroot, unpeeled, roots trimmed
2 tbsp olive oil
1 large banana shallot, peeled and finely chopped 
6 whole cardamom pods 
1 tsp ground cumin
1 tbsp lemon juice

Put two tablespoons of oil in a medium bowl with the garlic, ginger, lemon zest and crushed cardamom seeds. Mix to a rough paste, then add the fish and coat with the marinade. Cover the bowl, then put it in the fridge for at least an hour, preferably longer.

Bring a medium saucepan of water to a boil, then add the beetroot, cook for 40 minutes, until soft when pricked with a knife, then drain. When the beetroot is cool enough to handle, peel and discard the skin, then chop the flesh into 1cm dice. Put the oil in a large frying pan on a medium-high heat and, once hot, fry the shallot for seven to eight minutes, stirring once in a while, until caramelised and soft. Add the cardamom pods and cumin, fry, stirring constantly, for two minutes then stir in the diced beetroot, lemon juice and a third of a teaspoon of salt, and set aside in a warm spot.

Lift the fish out of its marinade, scraping off most of it but leaving a bit for flavour, then transfer to a plate; discard the marinade.

Put the flour in a medium bowl with half a teaspoon of salt and a good grind of pepper. Toss the fish in the flour to coat it on both sides, then shake off any excess. Put a large nonstick frying pan on a medium-high heat and add a tablespoon of oil and half the butter. Once the butter starts to foam, lay in half the mackerel flesh-side down and cook for two minutes. Flip over, fry for two minutes more, until cooked through, then remove from the pan, sprinkle with a pinch of salt and keep warm while you repeat with the remaining oil, butter and fish.

Divide the fish between four plates and squeeze over the lemon juice. Spoon the beetroot alongside and top that with a spoonful of yogurt. Gently swirl the yoghurt into the beetroot, so it ripples, then sprinkle with coriander and serve.