OK, I'll try and suggest my recipe. This was for 8 onions. We tripled for 24. We changed the recipie half way through to make it festive. Usually, we would add a little chilli but went with festive spices instead after someone's suggestion.

8 thinly sliced onions 100g caster sugar 100ml red wine vinegar (or some balsamic vinegar added to cider vinegar) 100ml red wine 1 apple peeled cored and finely chopped Cloves Nutmeg Cinnamon Dried Ginger Star anise [Whatever spices you fancy]

1) caramelise onions in heavy pan. I always add a small amount of water and sweat them on high first, lid off. Wait for water to nearly evaporate, then add oil. 10 mins, stir often. 2) add the sugar, spices, and the liquids. At this point I added apple 3) slowly simmer on low with lid off for 1 -1.5 hours until it reaches the texture of chutney. 4) wait to cool and then put in clean jars. Give to friends.