onion marmalade that will store for a couple of months?

[winnie]

Anyone? TIA

I have made Nigella's onion mush recipe but from memory that is just very slow-cooked onions with a little sugar to help them brown. But only keeps a week or so. Think you would need to add some more sugar and some vinegar to make it keep longer, ie make it more chutneyish.

Thanks MaloryTowers & BirdyArms.

None of the recipes I have found can be kept for any length of time and I want to make some to keep for Xmas and the New Year.

being hopeful