Insert a skewer through each aubergine and hold over the flame of a gas hob. Char the outside of the skin until it’s blistered and blackened and the flesh of the aubergine is soft when pressed. Leave until cool enough to handle then peel off the skin and discard. Set aside.

In a large preserving pan heat the olive oil on a medium heat. Add the onion and cook for about 15 minutes until it starts to caramelise.

Add the chill, ginger and garlic and cook for a couple of minutes.

Then add the rest of the ingredients, including the aubergine and bring to a boil.

Turn the heat down and simmer for 1 hour and check for seasoning.

Pour into a blender and whizz up until smooth.

Pour back into the saucepan and bring back to a boil.  Turn down to a simmer until it's reduced to the desired ketchup consistency which might be about half an hour.

Decant into sterilised jars. You can eat it straightaway or keep in a cool dark place for six months.