Ever wondered how to make caramelised onions? Whilst they do require a little time and some patience to make, your efforts will be rewarded with an infinitely useful jar of deeply savoury onions. Once you have made a batch, you will wonder how you ever did without them.
Total Time Investment: 1 hour, 10 minutes
We all have a little black dress (or is that LBD?). Something we can pull out of the cupboard at a moments notice and dress up or down according to the occasion. The old standby that never fails us. Caramelised onions are the culinary equivalent of that LBD. Having a jar in the fridge means you are ready for anything, be it a quick dinner at home or drinks with friends.
Whilst I find caramelised onions to be a great kitchen staple, I can’t pretend that there is not a time investment to actually make them. Because there is. They take a good hour to slowly cook down to sticky deliciousness. However they are not high maintenance, requiring nothing more than a quick stir now and again, so I make a batch when I have other things to do in the kitchen.
Do not try and rush the cooking process. Trust me, it will not go well. On those occasions I have tried to hurry things along, the onions have browned but not softened into the desirable sticky mass. Long, slow cooking allows the naturally high sugars in the onions to concentrate and caramelise, turning the onions soft and sweet. Caramelised onions are ready when they have turned a deep brown, and are so soft they can be easily squashed between your fingers. They will reduce significantly in volume as they cook, so don’t worry if your pan is initially piled high with onions as you start.
As to what caramelised onions are good for? Stuff caramelised onions into burgers or hot dogs, strew them over the base of a quiche, a goats cheese tart or a simple tarte tartin. Add them to pizzas, fold them into muffins, blitz the onions through hummus for a delicious caramelised onion hummus, use them to enrich your gravy, or simply serve them on cheese platter. There are an infinite number of uses for caramelised onions, and you are really only limited by your imagination.
Tips & Tricks for getting ahead with Caramelised Onions
- A jar of caramelised onions will keep for up to a month in the fridge.
- Freeze caramelised onions for longer term storage. Pack spoonfuls of the onions an ice cube tray and freeze. Transfer the frozen cubes to a zip lock bag, and add the cubes straight into soups or stews for a flavour boost.
- Got a recipe that requires you to sweat onions? Use a large scoop of caramelised onions in the recipe to save time.
- You can make caramelised onions in the slow cooker. Just follow the same recipe, and stir every few hours to ensure that the onions caramelise evenly.
- Give jars of caramelised onions as gifts. Your friends will thank you.
- Any type of onion can be caramelised, so use whatever you have available. I prefer brown or red onions, but have also used shallots an even leeks.
- Whilst there is only a small amount of sugar in the recipe, which helps with the final caramelisation, the recipe can be made without sugar. Just omit it completely, or substitute a small amount of maple syrup or honey in its place.
- I like to make my caramelised onions with balsamic vinegar, however I have also used red wine vinegar or even vincotto instead. The acid in the vinegar helps balance out the sweetness of the onions, but is not essential. It can be omitted completely.
- Caramelised onions can be made without butter (or ghee). It is the caramelisation of the sugars in the onion itself that produces the deep colour and sweetness.
- The butter just makes the onions more unctuous. Replace the butter with olive oil for a vegan version, or omit the fats completely. If you choose to omit oils, add a little water to the pan initially which will start to cook the onions.
Kitchen Basics: How to Make Caramelised Onions
- 2 Tablespoons butter, ghee or olive oil
- 5 large onions (approx. 1kg) finely sliced
- Pinch of sea salt
- 2 Tablespoons (40 ml) balsamic vinegar optional
- 1 teaspoon dark muscovado sugar optional
Melt the butter, ghee or olive oil in a heavy based fry pan over a low heat.
Add the onions and salt, and stir to coat with the melted fat.
- Allow to cook over a low heat, stirring every 5 - 10 minutes. As the onions start to caramelise, it will appear that they are sticking to the bottom of the pan. This is perfectly normal. Just scrape the sticky parts off the bottom of the pan and stir it back into the onions.
- When the onions are dark brown, soft and sticky (after approximately 1 hour) stir in the sugar and balsamic vinegar (if using)
- Continue to cook for another 2-3 minutes, or until the balsamic vinegar had evaporated.
- Remove from the heat, allow to cool slightly then place in a clean jar.
- Store in the fridge or freezer and use as desired.
You can use a food processor to slice the onions if you wish. I can't be bothered washing the dishes so just slice them with a knife.
You do not need to add the balsamic vinegar and sugar to the onions, but they do add a slightly deeper flavour. I always add it.
Store these in a clean jar in the fridge for up to one month. If you wish to keep them for longer, I recommend freezing them into meal size portions. I use ice cube trays.
These will be vegan if you use olive oil to caramelise the onions.