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Sweet Pickled Red Onions
Sweet pickled red onions are one of those little extras I always have in the fridge. I slice the onions thin and soak them in vinegar with a touch of sugar and salt until they’re vibrant, tangy, and just the right amount of sweet. They add the perfect sharp crunch to tacos, salads, burgers, and even smashed avo on toast. Quick to make and endlessly useful, they’re an easy way to lift the flavour of just about anything I’m eating. Simple, pretty, and packed with punch.
Ingredients
- 1 red onion, thinly sliced
- 1/2 cup red wine vinegar
- 2-3 tbsp caster sugar
- 2 tsp sea salt flakes
- 1 cup water
Instructions
- Add the sliced onions to a 500ml capacity jar.
- In a small pot, combine the red wine vinegar, caster sugar, salt, and water. Bring to a rapid simmer over low heat, stirring occasionally until the sugar and salt have dissolved.
- Carefully pour the hot pickling liquid into the jar over the onions.
- Allow to cool fully to room temperature, then seal with a lid and store in the fridge.
Notes
- These pickled onions are ready to eat within an hour, but they taste even better after sitting in the fridge overnight as the flavours develop.
- Slice the onions as thinly as you can. A mandoline makes this job quick and gives you perfectly even slices, but a sharp knife works just fine.
- I use these jars for pickling. They're the perfect size and seal tightly to keep everything fresh.
- Red wine vinegar gives a lovely depth of flavour, but white wine vinegar or apple cider vinegar work just as well if that's what you've got.
- The pickles will be slightly sweet and tangy with a nice bite. If you prefer them sweeter, add an extra tablespoon of sugar. If you like them sharper, reduce the sugar to 1 tablespoon.
- Make sure the onions are fully submerged in the pickling liquid. If they're not, press them down gently or top up with a little extra water.
- These keep in the fridge for up to 2 weeks in a sealed jar. The onions will soften slightly over time but remain perfectly crisp and delicious.
- Not suitable for freezing as the texture will turn mushy after defrosting.
- For extra flavour, add a bay leaf, a few black peppercorns, or a pinch of chilli flakes to the jar before pouring in the hot liquid.
What I Cook With
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Nutrition Information:
Yield:
10Serving Size:
1Amount Per Serving: Calories: 14Total Fat: 0gSaturated Fat: 0gTrans Fat: 0gUnsaturated Fat: 0gCholesterol: 0mgSodium: 467mgCarbohydrates: 3gFiber: 0gSugar: 2gProtein: 0g
Please note, this nutrition information is to be used as a guide only. Nutrition information isn’t always accurate.
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Sweet Pickled Red Onions Recipe
Because Tacos Deserve the Red Carpet Treatment
Throughout my childhood, tacos were the ultimate quick fix – the kind of dinner you could throw together in minutes when the household was in chaos and everyone was yelling about being starving. They were simple, straightforward, and fed the masses. But now? Tacos are a full-blown production in my kitchen. They’ve gone from Taco Tuesday night dinner to a proper day-long culinary event. I spend hours prepping fillings and toppings, and honestly, it’s my idea of bliss. I’m talking slow-cooked steak carnitas, creamy guac, zingy pico de gallo, sweet corn salsa, and my not-so-secret weapon – Sweet Pickled Red Onions.
Now, I know it sounds a little over the top, but hear me out. Each element adds something unique to the taco. A little tang here, a burst of freshness there, crunch, softness, heat. I want every taco to be its own little adventure, and to do that, I need the full rainbow of toppings. These pickled onions are an essential part of that lineup. They’re quick to make, can be prepared in advance, and have this magic ability to lift even the most mediocre taco to something worth writing home about.
They’re sharp, sweet, and a little bit sassy – the kind of topping that doesn’t need to shout to get attention but always ends up stealing the spotlight anyway. I can’t remember the last time I made tacos without them, and if I’m honest, I don’t think I ever will again. They just bring everything together in the most perfect way. You’ll see what I mean when you try them.
The Joy of Prepping for Tacos All Day
There’s something meditative about taking your time with food prep, and tacos give me the perfect excuse. When I’m making them, I’m not just chucking things into bowls. I’m soaking up the whole process – slicing, marinating, roasting, chopping, and of course, pickling. These sweet pickled red onions come together quickly, but they still feel like part of the ritual. They sit quietly doing their thing in the background while I sort out the rest of the feast.
Using a mandolin for slicing is my go-to. Not just because it’s faster, but because it gives you that perfect, thin uniformity that makes every bite delicious. Of course, if you’ve got knife skills, go for it – I won’t stop you. But if you’re like me and you’ve ever tried to multitask while slicing onions by hand, only to end up with a mix of paper-thin slivers and giant chunks – well, the mandolin starts looking pretty good.
I keep a few jars of these in the fridge on taco weeks, and they usually don’t make it past the first round. Not because they go off – they’ll easily last a week in a jar with a good lid – but because I find myself sneaking forkfuls out of the fridge. They go on more than just tacos, too. Try them on burgers, with grilled meats, or tossed through a salad. They’re versatile and absolutely moreish.
Why I’ll Never Go Back to Plain Onions
Back in the day, I’d just chuck some raw red onion on my tacos and call it a day. And look, they did the job. But the first time I made these sweet pickled red onions, I realised what I’d been missing. They’re like the glow-up version of raw onions – all the sharpness but mellowed out, with a little bit of sweetness and acid to tie it all together. I don’t mean to sound dramatic, but they changed the taco game for me.
They also work wonders for texture. That slight crunch and tang add the perfect contrast to creamy sauces, tender meats, and soft tortillas. It’s the balance of it all that makes me come back for more. And while they might seem like a little extra step, they take barely any time to make. I usually throw them together while something else is cooking – and by the time the tacos are ready, so are they.
It’s one of those recipes that once you make it, it becomes second nature. You’ll start to think, “Oh, I’ve got an onion – might as well pickle it.” And before you know it, you’ve got a jar in the fridge at all times. If you’re anything like me, you’ll start building meals around them just to have an excuse to use them – they’re that good. Honestly, they’re the kind of small thing that makes a big difference.
Ingredient breakdown
Red onion
Red onion rather than brown or white because the colour is part of the point. As the onion sits in the pickling liquid it turns a vivid, almost jewel-bright pink that looks genuinely beautiful on bruschetta, tacos, grain bowls, and anything else you spoon them over. Slice them as thinly as you possibly can because thinner slices pickle faster, soften more evenly, and are easier to eat without pulling the whole topping off in one go. A mandoline gives you perfectly even slices in seconds, but a sharp knife and a steady hand works just fine.
Red wine vinegar
Red wine vinegar is the pickling liquid base and it gives the onions a lovely depth and a slightly fruity acidity that suits the sweetness of the sugar really well. White wine vinegar or apple cider vinegar both work as substitutes if that’s what’s in the pantry, and each will give you a slightly different flavour profile. Apple cider vinegar makes a slightly mellower, more complex pickle. White wine vinegar is sharper and cleaner. All three are good. Red wine vinegar is just the classic choice here.
Caster sugar
The sugar is what makes these sweet pickled onions rather than just pickled onions, and the balance between sugar and vinegar is what gives them that addictive sweet-tangy quality. One and a half tablespoons is the sweet spot for a balanced pickle, but adjust to taste. An extra tablespoon if you want them sweeter and softer on the palate, drop back to one tablespoon if you prefer something sharper with more vinegar punch.
Sea salt flakes
Two teaspoons of sea salt flakes dissolve into the pickling liquid along with the sugar and season the onions as they sit. Salt also draws moisture out of the onion cells, which helps the pickling liquid penetrate more quickly and gives the finished pickle a better texture. Sea salt flakes dissolve cleanly without any of the harshness you can sometimes get from table salt.
Water
The water dilutes the vinegar to a pickling brine rather than a straight acid bath, which would be far too sharp. The ratio of vinegar to water here gives you a brine that is tangy and present without being mouth-puckeringly sour. Everything goes into a small pot together and gets brought to a rapid simmer so the sugar and salt dissolve completely before the liquid goes over the onions.
Serve this with
- Tacos, grain bowls, or alongside grilled meats as an all-purpose condiment worth keeping in the fridge at all times.
- Bresaola and goat’s cheese bruschetta, where the sweet acidity of the onions cuts through the richness of the cheese beautifully.
- Pulled pork sandwiches or burgers as a punchy, vibrant topping that cuts through the fat.
I love how easy this is to make! My family loved it!
Now I know exactly what to do with the onion I have leftover. Thanks so much for sharing this!
I’ve never made pickled onions, but this looks so good and easy to make.
Such an easy recipe for so much flavor. I can’t wait to try these on other things though they won’t last long in the frig.
I love how simple and quick this recipe is! We always have a jar of pickled onions in our fridge, it is one of my favourite condiments!