How to Make Caramelised Onions

Caramelised onions are easy to make, but need a lot of time to cook. If you see someone telling you they’re caramelising onions and it takes 15 minutes, or half an hour, those are not caramelised onions! They are lightly cooked.

So yes, it’s very time consuming, but not very much active work. If you pop them on the stove and work on other things, just coming back to stir every once in a while, you won’t even notice the time. Slow and low cooking is always worthwhile.

Add these to any savoury dishes for a touch of sweetness and a more complex flavour. These leek and onion pasties are a good example, but you can make caramelised onion hummus, or add to simple pasta dishes, or more complex meals like a savoury mushroom wreath.

This is a basic recipe you’ll want to have in your back pocket.

Scroll to the bottom of the post or click “skip to recipe” above to see the recipe card with full ingredient measurements and instructions.

Ingredients

Method

Heat the olive oil in a large frying pan over low heat. Halve and thinly slice the onions, then place them into the pan.

Cook, stirring occasionally, for about two hours. During this time the onions will slowly become translucent, then turn a light golden colour. They should reduce by at least half. If you see any browning, reduce the heat.

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Once the onions have caramelised, add the salt and pepper. Stir to incorporate, then add the wine. Stir through, cook for another five minutes, then remove from the heat.

Use the onions as you’d like, or refrigerate for up to a week in an airtight container. Freeze up to one month.

Tips and Notes

Caramelised onions freeze surprisingly well. I often make extra and freeze portions in airtight containers for later use, and recommend this, as it’s such a time consuming process.

Adding the wine (or balsamic vinegar) at the end of the cooking time deglazes the pan. This lifts all the delicious savoury bits that may have stuck to the pan during cooking and makes the onions much easier to remove. Win win.

It’s important to cook the onions on a really low temperature, and they should not be browning. Patience is the most important element.

Some people add a bit of sugar or honey to the onions to speed up the process slightly, which you can do, but I never bother.

Don’t worry about crowding the pan when you first add the onions. They’ll cook down significantly, as you can see above – my pan was overfilled and heaped over the edges when the onions were first added.

Substitutions

If you don’t drink wine or have it in the house, balsamic vinegar is an ideal sub here. Replace the full amount of wine with one tablespoon of balsamic vinegar. Apple cider vinegar works too.

Red, yellow, and white onions can all be used interchangeably. Shallots are good too (but more expensive).

More Staple Recipes

Pickled Red Onions
Vegetable Broth
Spelt Pasta
Oat Milk
Whole Egg Mayonnaise

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