First you have to chop up all the onions and the tomatoes, add a little salt, and then let it sit for 24 hours.
After that, it's a case of adding the rest of the ingredients and cooking it all down. I ended up halving the recipe amounts, just to make it tally with the amount of tomatoes I had, but I'm glad I did as I still ended up with about 5 jars and I think that's plenty for now, especially as it's an untried recipe!
I've tucked them away in a cupboard for now, but wondered if anyone knew what the best amount of time to leave them is before you start tucking in?
All info gratefully received!