Tip the halved potatoes into a large bowl with 3 tablespoons of the olive or neutral oil, the garlic, ginger, crushed spices (you can do these in a pestle and mortar or spice grinder), chilli powder and 1 teaspoon of sea salt flakes. Mix well.

In a separate bowl, mix the onion, ground cumin, ground coriander, the remaining 2 tablespoons of olive oil, the juice of ½ the lemon and another ½ teaspoon of sea salt flakes. Pile the mixture into the middle of a decent sized bit of foil, and make a neat parcel with the seam on top. Set aside.

Once your barbecue is ready, lay the potatoes on, cut side down, and cook covered for 20–30 minutes. Turn them over, lay the foil packet on the grill, and cook both for a further 20–30 minutes, until the potatoes are cooked through and the onions are tender.

Mix the onions and potatoes in a serving dish, adding the spiced oil from the foil packet, and mix in the chilli, the rest of the lemon juice and the coriander leaves. Taste and adjust the salt as needed, then scatter over the cashews and serve hot.