Prick whole aubergines all over (to stop them exploding!) and roast on 180c for about an hour. Whole aubergines are very flexible in the oven - you can cook them on a lower or higher temperature for a shorter or longer time. I have completely forgotten about them for hours and although they were somewhat shrivelled, they were still perfectly edible. I have it on good authority that they are even better when cooked over a lovely, smoky barbecue, but living in a flat I have not had the opportunity to test this and use smoke oil instead, as described above.

Blend in a food processor, then add enough salt and fresh lemon juice for it to take on some taste. It will still be a little bland but you can adjust it as necessary when you use it in future applications. Portion it up as you think necessary (I put about 200g in individual freezer bags) and freeze. It will keep, well packaged, for several months.

Blend fresh or defrosted aubergine purée with the yoghurt, then taste it. I have included general seasoning amounts about, but you should add the rest of the ingredients to taste as it will depend on your aubergines and your personal preferences.

In general, I would be heavy-handed with the salt and lemon juice, but add only a little cumin and even less smoke oil. The flavour of the garlic will really bloom in the fridge overnight, so bear that in mind when you're deciding how much to add - it can end up tasting very strong. When it is finished the mix should be wonderfully savoury and tart, with aftertastes of cumin and a little smoke. It should not actively taste salty, but should have enough seasoning to really bring out all the flavours. This can only be achieved with judicious use of salt.

Refrigerate until well chilled before serving.