Pickled Red Onions Recipe

Tangy, vibrant pickled red onions with a perfect crunch that brightens any dish from tacos to salads with their sweet-sour punch and gorgeous ruby hue.
Difficulty:
Beginner
Prep Time:
10 mins
Cook Time:
5 mins
Serves:
1 jar (about 2 cups)
An overhead shot of a mason jar filled with bright magenta pickled red onions, the vibrant slices showing through the clear glass. Some onions are artfully arranged on a rustic wooden board beside the jar, displaying their translucent, pinkish-purple rings. Soft natural light streams across the scene, highlighting the vivid color contrast between the onions and a sprinkle of black peppercorns and mustard seeds visible in the brine. A silver fork rests nearby with a few onion slices, suggesting immediate enjoyment, while tiny droplets of the pickling liquid create a glistening effect on both the jar and board.

Ingredients

<ul class="ingredients-main-list"><li class="ingredients-single-item">2 medium red onions</li><li class="ingredients-single-item">240ml white vinegar (apple cider vinegar or rice vinegar also work)</li><li class="ingredients-single-item">120ml water</li><li class="ingredients-single-item">2 tablespoons granulated sugar</li><li class="ingredients-single-item">1 1/2 teaspoons fine sea salt</li><li class="ingredients-single-item">1/2 teaspoon black peppercorns</li><li class="ingredients-single-item">1/2 teaspoon mustard seeds</li><li class="ingredients-single-item">1 bay leaf</li><li class="ingredients-single-item">1 clove garlic, peeled (optional)</li></ul>

Equipment

<ul class="equipment-main-list"><li class="equipment-single-item">500ml mason jar with lid</li><li class="equipment-single-item">Small saucepan</li></ul>
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Directions

<ol class="no-list-style"><li class="MethodStepper"><h4 class="step-title">Step 1</h4>Start by preparing your red onions. Peel them and cut off the root and stem ends. Slice the onions as thinly as possible (about 2-3mm thick) - using a sharp knife or mandoline for consistent, thin slices. The thinner you slice, the quicker they'll pickle and the better texture they'll have. Place the sliced onions in a clean 500ml mason jar, packing them in but not crushing them.</li><li class="MethodStepper"><h4 class="step-title">Step 2</h4>In a small saucepan, combine the vinegar, water, sugar, salt, peppercorns, mustard seeds, bay leaf, and garlic (if using). Heat over medium heat, stirring occasionally to dissolve the sugar and salt completely. This creates the brine that will transform the sharp raw onions into tangy, crisp pickles. Bring the mixture just to a simmer - you'll see tiny bubbles forming around the edges of the pan. Don't let it come to a rolling boil, as this can reduce the liquid too much.</li><li class="MethodStepper"><h4 class="step-title">Step 3</h4>Once the sugar and salt have fully dissolved (about 2-3 minutes), carefully pour the hot brine over the sliced onions in the jar, making sure to cover them completely. If some onion slices float to the top, gently press them down with a spoon to submerge them in the brine. The heat from the brine begins the pickling process and helps the onions absorb the flavors quickly while softening their texture slightly.</li><li class="MethodStepper"><h4 class="step-title">Step 4</h4>Allow the jar to cool uncovered at room temperature for about 30 minutes, or until it's no longer hot to the touch. You'll notice the vibrant magenta color beginning to develop as the onions release their natural pigments into the brine. This color transformation is not only beautiful but indicates that the pickling process is working.</li><li class="MethodStepper"><h4 class="step-title">Step 5</h4>Once cooled to room temperature, secure the lid tightly on the jar and place it in the refrigerator. For the best flavor and texture, allow the onions to pickle for at least 1 hour before serving, though they'll continue developing more complex flavors over the next 24 hours. The acid in the vinegar breaks down the cell walls of the onions, softening their texture and mellowing their sharp raw flavor.</li><li class="MethodStepper"><h4 class="step-title">Step 6</h4>Your pickled red onions will keep well in the refrigerator for up to 2-3 weeks. The flavor will continue to develop over the first few days, becoming more nuanced but still maintaining that perfect balance of sweet, tangy, and crisp. Use a clean fork or spoon whenever removing onions from the jar to extend their shelf life. Enjoy them on tacos, sandwiches, salads, grain bowls, or anywhere you need a bright pop of flavor and color!</li></ol>

Nutrition Facts (per serving)

🍽️ Serving Size: 1 serving
🔥 Calories: 23 calories
🥑 Fat: 0 g
🧈 Saturated Fat: 0 g
🍞 Carbohydrates: 5 g
🍭 Sugar: 3 g
🍗 Protein: 0 g
🫀 Cholesterol: 0 mg
🧂 Sodium: 145 mg

Chef’s Notes

A few helpful details for making this recipe.

How long do homemade pickled onions last in the fridge?

Properly stored homemade pickled red onions will keep for 2-3 weeks in the refrigerator. Always use clean utensils when removing onions from the jar to prevent contamination, and ensure they remain fully submerged in the brine for maximum freshness and flavour.

Can you pickle red onions without sugar?

Yes, you can make sugar-free pickled onions by omitting the sugar or using alternatives like honey, maple syrup, or stevia. The sugar primarily balances the acidity, so without it, your onions will have a sharper, more tart flavour profile but will still pickle properly.

What dishes are best enhanced with pickled onions?

Pickled onions brilliantly elevate tacos, burgers, sandwiches, avocado toast, grain bowls, salads, charcuterie boards, and grilled meats. Their vibrant tang cuts through fatty dishes, brightens creamy foods, and adds beautiful colour contrast to your plate. They're especially delicious with Mexican cuisine.

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