How to Caramelise Onions Properly, and the Shortcut for a Tuesday

By Jodie Smith, Product & Hamper Manager at The Gourmet Pantry.

Caramelised onions take about 40 minutes over low to medium heat, with no sugar and no lid. Slice them thinly, salt them early, and stir every few minutes while they go from raw to soft to deep bronze. Anything quicker is fried onion, a fine thing to eat, just not the same ingredient. If 40 minutes is not on offer tonight, a 360g jar of Caroline's Caramelised Onions spoons straight onto a sandwich or a cheese board instead.

Why 40 minutes is the real number

Two things happen in the pan, and they happen in order. First the onions have to lose their water. An onion is mostly water, and until the bulk of it has steamed away nothing can brown. Only then do the sugars start to caramelise and the proteins start to brown, which is where the colour and that low savoury sweetness come from.

Heat will not bring that forward. Turn the burner up and the edges blacken while the middle is still wet, and what you get is bitter rather than sweet. Recipes promising caramelised onions in ten minutes are describing softened, lightly browned onions. Good on a burger, but not the jammy brown tangle that goes into a French onion soup.

The pan matters more than the variety of onion. Depth is the problem: onions piled 5cm deep steam themselves and stay pale. Spread the same quantity across a wide, heavy based frying pan or a shallow casserole and they have room to give up their water first and brown second.

The method, step by step

1. Start with 1kg of brown onions, about six medium ones. They cook down to roughly two cups, which feels like a swindle until you taste them.
2. Halve each onion through the root, sit it flat and slice thinly from root to tip rather than across. Cut this way the slices hold together instead of collapsing into threads.
3. Heat 30g of butter with a tablespoon of olive oil in your widest heavy pan over medium heat. The oil stops the butter catching later on.
4. Add the onions and a solid pinch of salt. Salting early pulls the water out and shortens the first stage.
5. Keep the heat at medium for the first 10 minutes, stirring now and then, until the pile has slumped and turned translucent.
6. Drop to low and settle in. Stir every four or five minutes for the next 25 to 30. They turn gold somewhere around the 20 minute mark; the last 10 minutes are where they go bronze and sticky.
7. When a brown crust builds on the base of the pan, splash in water, wine or a little sherry vinegar and scrape it back through. Do this two or three times. That crust is most of the flavour.
8. Finish with black pepper, and a teaspoon of balsamic if you want them sharper. Cool them, then keep in the fridge for five days or freeze in tablespoon portions for three months.

Cook a kilo rather than two onions. The work is identical, and the freezer portions are the point.

The shortcut for a Tuesday

Nobody stands over a pan for 40 minutes at seven o'clock on a weeknight. This is exactly what the Belazu Flavour Hack Caramelised Onion is for. One tablespoon does the work of one medium caramelised onion, so a 130g jar carries about six of them, and it costs $9.95.

Being honest about what it can and cannot do matters. Stirred into mayonnaise, sizzled in butter as the base of a sauce, blended into a dip or a dressing, folded through mash or dropped into a ragu, it is indistinguishable from the effort. What it will not give you is texture: those soft brown strands you want draped over a steak or layered into a tart only come from the real thing. Flavour, jar. Texture, pan.

It sits in a Belazu range of three, all 130g and all $9.95. The Flavour Hack Roasted Garlic works the same way, a tablespoon standing in for a roasted clove, and the Flavour Hack Balsamic Sundried Tomato is sun dried tomato blended with balsamic vinegar of Modena, which is the one to reach for when a tomato sauce tastes thin.

A paste is not a relish, and the difference matters when you are shopping. A relish is already a condiment, sweetened and soured and meant to be spooned straight onto something cold. Caroline's Caramelised Onions, 360g from the Tasmanian Gourmet Kitchen, is that job: cheddar and pickle sandwiches, a sausage roll, the corner of a cheese board. The Flavour Hack jar is a cooking ingredient that goes in early. Most kitchens end up with both.

Where a spoonful of them goes

Once there is a tub in the fridge the uses find you. Under a fried egg on toast. Folded through mashed potato with a lot of butter. Between the cheese and the bread in a toastie, so it melts into the cheddar. Stirred into gravy, or into the pan juices after a roast chicken. Whisked with mustard and red wine vinegar into a dressing that makes a plain green salad taste cooked.

For anything you are handing around, the fastest route is a pastry case. Confiletas mini savoury pastry cases are 37mm across and come twelve to a box, ready to fill: a teaspoon of onions, a little gruyere, three minutes in a hot oven. We wrote a longer piece on what to do with a box of pastry cases, and the same cases take a jar of tapenade just as happily when you want a second tray with no cooking at all.

Caramelised onion questions we get asked

What onions are best for caramelising?

Brown onions. They hold enough sugar to reward the time, they keep their shape through 40 minutes of stirring, and they are cheap enough to buy a kilo at a time. Red onions caramelise but turn a dull greyish purple and stay sharper. White onions are milder and give you less to work with. Shallots are lovely and cost four times as much. Whichever you buy, pick firm ones with tight papery skins.

Can you caramelise onions in advance?

Yes, and it is the only sensible way to do it. Cooled and packed into a jar with a film of oil over the top they keep five days in the fridge. For longer, freeze them in an ice cube tray, tip the cubes into a bag and use them within three months. One cube is roughly a tablespoon, which is the amount most recipes want. Reheat in a dry pan for a minute.

Do you need sugar to caramelise onions?

No. Onions carry plenty of their own, and added sugar mostly buys you colour rather than depth. If they taste flat at the end the cause is usually undersalting or a pan that never got hot enough to build a crust, not a shortage of sweetness. Some recipes add a pinch to speed the browning along, but a teaspoon of balsamic or sherry vinegar at the end does more for the same trouble.

Forty minutes, or one tablespoon

Learn the long way once, on a Sunday, with a kilo of brown onions and a wide pan, and freeze what you do not use. Keep a Belazu Flavour Hack Caramelised Onion in the cupboard for the nights when 40 minutes is not on offer. Both live near each other in our range of gourmet condiments, next to the pestos, harissas and relishes that solve the same problem in a different flavour. If you are buying for someone else, a working jar is a better present inside a box than on its own, which is what our Christmas hampers are for.