I saw a comment on a forum last week where a poster said she’d caramelised onions in a slow-cooker. To be honest I was very sceptical; surely you need the direct heat of a hob to get a good result? Won’t they just steam and go soggy? How does all the liquid evaporate? There was only one thing to do – have a go!
I had a look on the web, but although there were plenty of people who said they’d done it, no-one seemed to give definitive instructions. They generally seemed to go along the lines of “Add some butter to your onions and cook until done” Yup…really helpful, thanks for that!
So, as usual, I made it up as I went along and, having done it, I can definitely say…it works!
The hardest part was peeling and slicing all the onions, my eyes were streaming like mad, but it's a great way to get a decent quantity of onions caramelised, which you can then portion up and keep in the freezer until you need them. I use them regularly in nut roast, on pizza, in toasted cheese sandwiches, quiches, French onion soup and a zillion other ways so having them ready-to-use is a real time-saver.
Cook for two hours on ‘high’, stir the onions well, then cook for nine hours on ‘low’ (I left it overnight – the smell when we woke was lovely!) In the morning there was much less liquid than I expected, only about ½ cm, so I gave it all a stir and propped open the lid a little to let the steam escape then turned it up to ‘high’ for another two hours. That’s it!