These sweet-and-sour pickled onions bring a fresh, crunchy twist to all kinds of dishes. They’re surprisingly versatile and pair perfectly with salads, burgers, sandwiches or as a side with roasted meat. Make a batch with this simple recipe and discover how extra flavour enhancers can elevate the result!
An Ancient Preserving Method with Centuries-Old Roots
Preserving in vinegar and sugar isn’t a new trend — it’s one of the oldest techniques in the world. Long before refrigerators existed, people used vinegar, salt and sugar to make vegetables and fruit last longer. Vinegar lowers the pH-level, making it much harder for bacteria and moulds to grow. Sugar not only helps preservation, but also gives a nice balance to flavour.
In the 17th and 18th centuries, sweet-and-sour pickling was popular among sailors and soldiers, because preserved vegetables were easy to digest and could be stored for a long time on ships or in army depots. Also in farm-house kitchens, preserving vegetables was part of the annual routine. In late summer and autumn, the pantry would be filled with jars of gherkins, pickled pearl onions and beet-roots — a guarantee of vegetables on the table during the cold winter months.
Perfect for the Snack Platter
Sweet-and-sour onions are also real mood-setters on a charcuterie board or cheese platter. The fresh acidity cuts nicely through the richness of cheese and cold meats. Especially with creamy cheeses like Brie or Camembert, they provide a lovely contrast. With pâté or rillettes they also work perfectly, because they make the dish feel a little lighter.
For a summer aperitif you can combine them with olives, roasted nuts and some freshly baked bread. In winter they go beautifully with stews or game dishes. So you’ll have year-round pleasure from a few jars of sweet-and-sour onions in the cupboard.
Choosing Your Flavour Enhancers
The beauty of pickling onions in sweet-and-sour is that you can endlessly vary the flavour by adding herbs, spices or even different types of vinegar. Here are some ideas:
- Herbs: Fresh basil, dill, thyme or rosemary give a mild, herbaceous note to the pickled onions. Basil is especially recommended, because its fresh aroma enhances the natural sweetness of the onion.
- Spices: Black peppercorns, juniper berries and cloves bring warmth and depth to the flavour. Juniper berries add a subtle pine-like aroma, which goes beautifully with the vinegar’s tang. A few cloves give a warm undertone — especially lovely in autumn and winter.
- Citrus peel: Add a strip of lemon or orange peel for a fresh, lively hint. This works especially well in lighter dishes and salads.
- Chili flakes or sliced chili pepper: For a spicy twist you can add some chili flakes or a fresh chili pepper to the jar. This gives a subtle kick that pairs well with the sweet-sour profile.
Tip: Basil!
When preserving cherry tomatoes I discovered that a few fresh basil leaves make a real flavour explosion! Add a couple of leaves when filling the jars. After about a week, those few leaves will have flavoured the whole jar of onions.

What You Need to Make Pickled Onions
For about 3 jars of 250 ml (≈ 8.5 oz) each
- 3 large onions (or 4 to 5 smaller)
- 300 g vinegar (8%) → approx 10.6 oz / ~1 ¼ cups
- 150 g sugar → approx 5.3 oz / ~¾ cup
- 100 ml water → approx 3.4 oz / ~⅓ cup (if you use 6% vinegar you may omit the water)
- Salt and pepper to taste
- Optional: flavourings such as basil, peppercorns, juniper berries or cloves
Let’s Get Started
Preparing the onions
Peel the onions and slice them into thin half-rings.
Making the vinegar mixture
Combine the vinegar, sugar and water in a pan. Optionally add salt and pepper for extra flavour. Want to give the onions a unique aroma? Add flavourings like peppercorns, juniper berries or cloves.
Slightly briefly cook the onions
Add the onion rings to the vinegar mixture and let them cook for about 30 seconds. You can choose whether you want to do this or not — I do it because otherwise the vinegar mixture cools down too much when poured over cold onions, with the result that the jars often don’t vacuum-seal. By warming the onions briefly they will vacuum-seal properly.

Filling the jars
Spoon the onions and the vinegar mixture into sterilised 250 ml jars. Gently press the onions down so they are well submerged in the liquid. If you’re using fresh herbs like basil or dill, add them now. They’ll give a fresh, aromatic touch to the sweet-and-sour onions.
Sealing and storing
Seal the jars well and allow them to cool completely. Store the jars in a cool, dark place. After about a week, the flavours have fully developed and the onions are deliciously flavoured!
Using Sweet-and-Sour Onions in Dishes
Sweet-and-sour onions bring fantastic flavour and texture to many dishes. Try adding a spoonful of these pickled onions to salads. In a Greek salad I find them absolutely top! They pair perfectly with fresh leafy greens, tomatoes and creamy dressings. Or use them as a flavourful topping for burgers, wraps, or tacos. The tangy taste gives a fresh counterpoint to the rich, savoury flavours of those dishes. They also work excellently in pasta salads or grain bowls, and on a cheese plate they add colour and flavour.
Want to try something different? Serve these pickled onions as a side with grilled meat or roasted vegetables. The sweet-and-sour taste provides a beautiful balance and makes the dish feel lighter. Moreover, you can prepare the onions in advance, giving you a ready-to-go flavour booster that stays good for weeks in the fridge.

Red onions
Red onions give a beautiful, intense colour to your sweet-and-sour onions and taste slightly different. Due to their colour the onions in the jar gain a gorgeous deep-pink tint — great as a garnish on salads, wraps or burgers. Or try a mix of different colours. Also lots of fun!
Not Just for Onions
Although onions are fantastic for pickling, this method works perfectly for other vegetables too. Cucumbers are of course the classic, but also peppers, carrot sticks, cauliflower florets and even small tomatoes do well in a sweet-and-sour mix. By varying herbs and spices you can constantly discover new flavour combinations.
Mixed jars are also very fun: thinly sliced red onion together with cucumber slices and some radish for an extra spicy twist. That way you have in one jar a colourful garnish for sandwiches, burgers or as a fresh topping with grilled meat.
Have you caught the pickling bug? Here are some other fun recipes:



