Quick Pickled Red Onions for Salads and Sandwiches

There are few things I make more often than a jar of quick pickled red onions. They take less than an hour from board to first bite, and they keep for weeks in the fridge. That sharp, pink tangle is the difference between a good sandwich and a great one. Best of all, they ask almost nothing: a red onion, vinegar, salt, sugar, and a few minutes.

The Case for Keeping a Jar in the Fridge

In Mediterranean-inspired cooking, acidity is a seasoning, not an afterthought. Think of the pickled turnips alongside mezze, the vinegar-spiked onions in a Greek salad, the sharpness that makes a falafel wrap sing. Quick pickled red onions sit in that tradition but are faster and more forgiving than a ferment. You are not preserving for winter; you are brightening tonight's dinner.

For kitchen gardeners, red onions are one of the easiest crops. They are undemanding, store well, and smaller bulbs are perfect for pickling. A handful of sets planted in spring will reward you with bulbs by late summer. When you have more than you can use, this is the recipe to turn to.

What You'll Need (and Why It Works)

The formula is simple: sliced onion, a vinegar brine, and a little time. The brine softens the onion just enough while keeping its crunch. For a 500ml jar:

• 1 large red onion (or 2-3 smaller homegrown ones), peeled and thinly sliced.
• 150ml white wine vinegar or cider vinegar. White wine is my default for a clean, sharp flavour.
• 150ml water. This dilutes the vinegar so the onions are pleasantly sharp, not punishing.
• 1 teaspoon fine sea salt and 1-2 teaspoons caster sugar. Sugar balances the vinegar.
• Optional extras: black peppercorns, a bay leaf, garlic, chilli flakes, or orange zest.

You will also need a clean 500ml jar with a tight-fitting lid. Sterilise it if keeping for more than a couple of weeks; for a quick batch, a hot soapy wash and rinse is enough.

Method: From Board to Jar in Under an Hour

Slice the onion as thinly as you can. For a milder result, soak the slices in cold water for ten minutes, then drain well. Pack them into your jar, adding any optional aromatics between the layers.

In a small saucepan, combine the vinegar, water, salt and sugar. Heat over a medium flame, stirring until dissolved. You do not need to boil it, but it should be hot and steaming. Pour the hot brine over the onions, filling the jar to the top. Press the onions down so they are mostly submerged.

Let the jar cool for 30 minutes. That is the minimum time for the onions to soften and take on flavour. They are ready then, but improve after an hour or two. Seal and store in the fridge.

Chef's tip: For a brighter pink colour, use red wine vinegar. For a softer, sweeter pickle, use cider vinegar and an extra teaspoon of sugar.

Growing Your Own Red Onions for Pickling

Red onions are a rewarding crop for the British kitchen garden. Plant sets in early spring, about 10cm apart, in a sunny spot with well-drained soil. Keep them weed-free and water in dry spells. By late summer, when the tops yellow and flop, stop watering and let them dry. Lift on a dry day and cure in a warm, airy place for a couple of weeks.

For pickling, choose smaller bulbs, about 4-6cm across. They slice neatly and fit into jars. Varieties like 'Red Baron' give deep red rings that look beautiful in the jar. Any surplus can be frozen, but quick pickling is the fastest way to enjoy them.

Ways to Use Your Quick Pickled Red Onions

Once you have a jar in the fridge, you will reach for it constantly. A few favourites:

• Sandwiches and wraps: Layer into a cheese sandwich, chicken wrap, or falafel pitta.
• Salads: Scatter over a Greek salad, grain bowl, or tomato and cucumber salad.
• Cheese boards: Serve alongside sharp Cheddar, goat's cheese, or feta.
• Tacos and quesadillas: Spoon over black beans, avocado, and lime.
• Hummus and dips: Pile on hummus, baba ganoush, or labneh with olive oil.
• Warm dishes: Stir through lentils, spoon over grilled halloumi, or add to a jacket potato.

They are also excellent in tuna mayo, on a burger, or chopped into a vinaigrette.

Storage, Variations and Troubleshooting

Keep the jar in the fridge. The onions keep for at least two weeks, often three or four. They lose a little crunch over time but remain good. Use a clean fork to fish them out, and keep the remaining onions submerged. If the brine drops, top up with vinegar and water.

Variations are endless: add sliced chilli for heat, thyme or oregano for a Mediterranean note, or honey instead of sugar. You can pickle radish, carrot ribbons, or fennel in the same brine.

If too sharp, stir in more sugar. If too sweet, add vinegar. If too soft, the brine was too hot; let it cool a minute next time. If the raw onion flavour is strong, soak the slices first. Once you make a batch, you will wonder how you managed without a jar.