Caramelised Balsamic Onions
This will make you want to go and make a roast beef sandwich immediately. Seriously.
Don’t rush caramelising the onions. They need to go low and slow! This is where all that amazing deep, sweet flavour will come from. Expect they will take at least 20min in the first cooking step. See notes below for more thoughts.
I waterbathed this and have it on the shelf, however, it is not a tested recipe. If concerned, my recommendation would be to water bath and store it in the fridgege (perhaps a half batch) - it’s better eaten chilled anyway. See notes below for further thoughts.
Ingredients
To make approximately 8 half pints
16 cups red onions - peeled, halved & thinly sliced lengthways
2/3 cup brown sugar
2/3 cup balsamic vinegar - min 5% acidity
1 1/3 cups red wine (e.g. shiraz)
1/8 tsp salt
Pinch of black pepper
Optional - 1/4 tsp red chilli (red pepper) flakes
Method
Put your sliced onions and brown sugar into a large pot or deep-sided pan over a medium to low heat. Stir to combine.
Cook onions and sugar over medium to low heat, stirring regularly, until caramelised - minimum 20min (See notes)
While onions are cooking, prep your jars and lids. This is being water bathed for 10min, so jars and lids don’t need to be sterilised, just clean and warm.
Add the balsamic vinegar and red wine to the pot, stir to combine. Bring pot to a boil, then reduce heat and simmer.
If adding chilli flakes, add to pot and stir.
Simmer, stirring occasionally, until the liquid has thickened and mostly evaporated. (See notes)
Add salt & pepper to taste.
Place onions into clean jars, water bath for 10min (adjusting as required for altitude). Leave to sit for 12-24 hours before removing rings and checking seals.
(NOTE if you don’t want to waterbath, make a smaller quantity, 1-2 jars worth, then store in fridge to consume in 1-2 weeks)
Wash jars and store in cool dark place with rings off jars.
How to eat this
Amazing on roast beef or steak sandwiches
Goes well with any sort of barbequed/grilled meats
Add a good dollop to a cheese toastie (grilled cheese). Just trust me.
Recipe Notes
16 cups of sliced onions is loosely around 1.6kg
Don’t try and rush the caramelisation process. Depending on your onions, the size of your pan and a million other variables it may take longer than 20min (even double that time). If you do want to try and speed up the process, do not increase the heat - split the onions into two pans, the recombine once caramelised.
After you’ve added all the liquid and cooked down, you want the remaining liquid to be fairly thick and syrupy - but remember it will thicken up more as it cools.
This is not a ‘tested’ recipe, and is probably as far as I would stray from a tested recipe. I have compared the ingredients and their ratios to those in tested pickled onion and relish recipes; the finger content is lower than in those recipes. However, as the onions are caramelised before going into the jar, a lot of their moisture is removed, meaning the acidity ratio would increase versus the raw volumes. As per above, if concerned, consider making this (still water bath) and then store in the fridge.