Grease a loaf tin with a little oil then line it with cling film, leaving some overhanging the edges of the tin.,

Roughly chop the pistachios.,

Remove the cardamom seeds from the pods, discard the pods and grind the seeds until fine.,

Add to a large mixing bowl with 30g of the chopped pistachios, the tahini, vanilla and sea salt and beat until smooth.,

Place the sugar and 75ml of water in a medium saucepan and gently bring to the boil over a medium heat.,

Gently swirl the pan, do not stir the syrup or the sugar will crystallise.,

Once it starts to bubble, reduce the heat to low and leave to simmer for around 12–15 minutes, until you have a thick syrup.,

If you have a sugar thermometer, it needs to reach 121°C.,

When it is ready, add the tahini mixture to the pan (you don’t want the mixture to cool down, it needs to stay in the warm pan) and quickly beat the two elements together to make a smooth paste.,

This is best done with a wooden spoon or spatula.,

Try not to overwork it, though, as this will make the halva crumbly – you only want to beat it for 30 seconds.,

As soon as it is smoothly combined, spoon it into the lined tin and press on the remaining pistachios.,

Leave to cool.,

Once cool, cover with the cling film edges and transfer to the fridge to set overnight before serving.