An image of a chef frying onions

How to chop and fry onions properly (plus recipes)

How do you achieve 'translucent', 'golden brown', or 'caramelised' fried onions? Learn how to fry onions properly, then use your newfound skills in one of our wonderful onion recipes. Plus: how to chop onions video.

You can make a recipe in 15 minutes (of course you can), but should you? Slinging something together is fine when you’re really short of time, but some things demand more commitment. Like frying onions.

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Frying onions is at the core of lots of recipes, and if you don’t cook them to the degree you are supposed to then your meal won’t be as good. Under-cooked onions can give off acidic juices that, if you are adding them to anything creamy like a dauphinoise, will split a sauce.

They may also still be crunchy, a crime when studded through a soft, custardy quiche filling. As for recipes where you want not just soft onions, but golden or dark brown ones, you have to put in the hard yards first. Soft and translucent onion turns to gold and then brown as the sugars within it are liberated and caramelised.


Our onion dictionary

Here’s a handy check-list so you know what’s what:

Sweat the onions. Not a term we use at olivemagazine.com, because it sounds so grim; we prefer ‘fry’. However, what this means is to cook the onions in fat of some sort over a low to medium heat until they start to ‘sweat’ moisture. Once they have done this you can move on.

Frying until they are soft and translucent. This means frying gently, stirring often until they are soft enough to squish easily between you fingers but are still not the slightest bit brown. It will take you about 10 minutes to reach this point.

Cook until golden or brown. If you want golden onions then turn up the heat a little, but not beyond medium. Keep cooking and moving the onions around to keep the colour even. Stop when they are the colour you want. Add between 5 and 10 minutes to the original time.

Caramelise the onions. Take them beyond the point of brown: they will get softer and sweeter as you cook. Again, stick to a medium heat or they will burn around the edges. This can take a long time, up to 45 minutes if you have a big panful. It’s also at this point you’ll realise that a huge pile of raw sliced onions will cook down to a modest pan of caramelised onions. Onion tarts are a lot of work, but worth it.

Crisp, browned onions for finishing Indian dishes. This level of browning needs more fat to start with. Once the onions have gone to the limit of caramelisation and are very dark brown, lift them out of the pan and drain them on kitchen paper.


Three onion recipes to try

Gruyère and caramelised onion tart

1 hour, serves 8, easy

step 1

Heat the oven to 190C/fan 170C/gas 5. Roll out the pastry and line a 23cm tart tin. Line with paper and fill with baking beans then blind bake for 15 minutes. Remove the paper and beans and cook for another 10 minutes. Cook the onions in the butter over a low heat until caramelised, this will take about 30 minutes so be patient. Mix the cream, eggs, gruyère and thyme, and season. Stir in the onions. Pour into the tart case. Sprinkle over the parmesan. Cook for 20-25 minutes until just set. Serve at room temperature.

per serving 559 kcals, protein 12.5g, carbs 31.3g, fat 43.4g, sat fat 25.2g, fibre 2.5g, salt 0.79g


Sausage röstis with caramelised onion gravy

1 hour, serves 4, easy

sunflower oil

sausages 8 (apple, leek, sage and mustard flavours all work well)

King Edward potatoes 4 large

thyme 3 sprigs, leaves stripped

grainy mustard 2 tbsp

English mustard powder 2 tsp

egg 1, beaten

gravy

onions 2, thinly sliced

butter 25g

brown sugar 1 tbsp, any kind

plain flour 2 tbsp

chicken or vegetable stock 500ml

Worcestershire sauce 1 tbsp

step 1

Heat the oven to 180C/fan 160C/gas 4. Brush 1 tbsp oil over a shallow roasting tin, about a4-sized, or a round ovenproof pan, about 20-22cm across.

step 2

Brown the sausages in 1 tsp oil for 5 minutes or until golden. Grate the potatoes (no need to peel them), put into a clean tea towel and squeeze out as much water as you can. Tip into a bowl and mix in the thyme, half the grainy mustard, all the mustard powder, the egg and ½ tsp salt plus some black pepper. Tip into the roasting tin and add the sausages. Brush a little oil over the potato and bake for 45-50 minutes until the sausages and potato are crisp, golden and cooked through.

step 3

While the sausage röstis are baking, make the gravy. Put the onions and butter in a frying pan and cook gently until really soft and starting to caramelise – about 20-30 minutes. stir in the sugar, and brown over a higher heat for a couple of minutes, then stir in the flour, mixing until it has blended in. Gradually stir in the stock, followed by the remaining 1 tbsp grainy mustard and worcestershire sauce. Bring to a simmer and bubble, then reduce until it has a good consistency. Season to taste. Scoop the sausage röstis straight from the tin and serve with green veg and plenty of gravy.

per serving 752 kcals, protein 25.4g, carbs 68.6g fat 40.2g, sat fat 14.3g, fibre 7g, salt 4.6g


Pissaladière with apple, caramelised onion, fontina and watercress

1 1/2 hours + rising time, serves 6, a little effort

strong white bread flour 550g

dried yeast 2¼ tsp

olive oil

onions 4, peeled, halved and very finely sliced

rosemary 1 sprig, chopped and mixed with 50ml olive oil

sea salt flakes

fontina cheese 250g, diced

watercress 2 handfuls, any woody stems removed

Cox or Worcester apple 1, cut into matchsticks

step 1

To make the dough, mix 100g of the flour with 150ml of warm water and all the dried yeast in a mixing bowl. Cover the bowl with clingfilm and leave for 2 hours.

step 2

To make the caramelised onions, put the sliced onions into a pan heated with 1 tbsp of oil. Cook over a moderate heat until caramelised and very soft, adding a tiny splash of water if they get too dried out. This could take up to an hour or more. Cool then chop to a rough paste.

step 3

Uncover the bread bowl. The dough inside will be bubbly and very slightly risen. Transfer it to the bowl of a stand mixer and add the rest of the flour, 300ml warm water, 3 tbsp olive oil and 3 tsp salt. Mix everything with a wooden spoon just to get it started and then attach the dough hook to your machine and mix on medium speed. The dough will seem quite wet but do not add any more flour. Keep mixing until it comes together as a silky textured ball of dough (this could take 10 minutes or more). Put into a large, clean bowl and leave for about 1 hour until almost doubled in size.

step 4

Uncover the bowl then push the dough gently back into itself in a couple of places and form it into a ball. Cut into 2 pieces and shape each into a rough ball shape. Lightly dust the worktop with a little flour and roll out into rounds about 1 cm thick.

step 5

Heat the oven to 220C/fan 200C/gas 7 and put a pizza stone or very heavy baking tray in to heat up.

step 6

Spread half the onion across the top of one of the discs in a thin layer. Spoon over some of the rosemary oil and sea salt across the surface and scatter over half the fontina.

step 7

Carefully lift the dough directly on top of the hot stone or tray in the oven and bake for about 15 minutes, the top should colour slightly and the base and edges will crisp. Repeat with the other bread. Top with watercress and apple and drizzle over a little olive oil before serving.

per serving 623 kcals, protein 24.1g , carbs 24.1g, fat 23.9g, sat fat 9.6g, fibre 4.6g, salt 3.4g


How to chop an onion: video


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Header image courtesy of Getty