Name: Pickled Red Onions
Ingredients: Here’s a closer look at what goes into this recipe and why each ingredient matters.; For the Onions; Red onions — The star of the dish. Red onions are ideal for pickling because of their vibrant color, which turns an even more brilliant pink once pickled, and their slightly sweeter, milder flavor compared to yellow or white onions.; Garlic — Thinly sliced garlic infuses the brine with a warm, savory depth and becomes deliciously tangy and mellow itself after pickling.; Mustard seeds — These add a subtle tangy, slightly peppery pop of flavor and are a classic addition to pickling brines.; Red pepper flakes — A touch of heat that balances the sweetness of the brine. This can easily be adjusted up or down based on your spice preference.; Fresh dill (optional) — Adds an herbaceous, slightly citrusy note that pairs beautifully with the tanginess of the vinegar. This is a great addition if you’re planning to use the onions on sandwiches or alongside seafood.; For the Pickling Brine; Apple cider vinegar — The backbone of the brine, providing tang and acidity while also contributing a subtle, slightly fruity flavor that pairs beautifully with red onion.; Water — Balances out the acidity of the vinegar so the brine isn’t overly harsh.; Granulated sugar — Adds a touch of sweetness that balances the tartness of the vinegar, creating that signature sweet-and-tangy pickle flavor.; Salt — Essential for flavor balance and also plays a role in the pickling process itself.; Black peppercorns — Infuses the brine with a warm, subtly spicy background note as it simmers.

Ingredients

Here’s a closer look at what goes into this recipe and why each ingredient matters.

For the Onions

Red onions — The star of the dish. Red onions are ideal for pickling because of their vibrant color, which turns an even more brilliant pink once pickled, and their slightly sweeter, milder flavor compared to yellow or white onions.

Garlic — Thinly sliced garlic infuses the brine with a warm, savory depth and becomes deliciously tangy and mellow itself after pickling.

Mustard seeds — These add a subtle tangy, slightly peppery pop of flavor and are a classic addition to pickling brines.

Red pepper flakes — A touch of heat that balances the sweetness of the brine. This can easily be adjusted up or down based on your spice preference.

Fresh dill (optional) — Adds an herbaceous, slightly citrusy note that pairs beautifully with the tanginess of the vinegar. This is a great addition if you’re planning to use the onions on sandwiches or alongside seafood.

For the Pickling Brine

Apple cider vinegar — The backbone of the brine, providing tang and acidity while also contributing a subtle, slightly fruity flavor that pairs beautifully with red onion.

Water — Balances out the acidity of the vinegar so the brine isn’t overly harsh.

Granulated sugar — Adds a touch of sweetness that balances the tartness of the vinegar, creating that signature sweet-and-tangy pickle flavor.

Salt — Essential for flavor balance and also plays a role in the pickling process itself.

Black peppercorns — Infuses the brine with a warm, subtly spicy background note as it simmers.

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Instructions

1. Slice and Pack the Onions

Thinly slice the red onions — a mandoline works wonderfully here for consistent, thin slices, though a sharp knife works just fine too. Pack the sliced onions into a clean glass jar, pressing down gently so you can fit as much as possible without overly crushing them.

2. Add the Aromatics

Add the sliced garlic, mustard seeds, red pepper flakes, and fresh dill, if using, directly into the jar with the onions. These aromatics will infuse the brine as it’s poured over the top and continue to flavor the onions as they pickle.

3. Make the Brine

In a small saucepan, combine the apple cider vinegar, water, sugar, salt, and black peppercorns. Bring the mixture to a gentle simmer over medium heat, stirring occasionally, until the sugar and salt are completely dissolved.

4. Pour the Hot Brine Over the Onions

Carefully pour the hot brine over the packed onions in the jar, making sure the onions are completely submerged. If needed, use the back of a spoon to press the onions down so they’re fully covered by the liquid.

5. Cool, Seal, and Refrigerate

Let the jar cool to room temperature on the counter, uncovered, to avoid trapping excess steam and condensation inside. Once cooled, seal the jar with a tight-fitting lid and transfer it to the refrigerator.

6. Let Them Pickle

Allow the onions to pickle for at least 1 hour for a quick, mild pickle. For a deeper, more developed tangy flavor, let them sit for several hours or overnight before using.

7. Store and Enjoy

Keep the jar refrigerated at all times. Use the pickled onions on tacos, burgers, sandwiches, salads, rice bowls, grilled meats, and any other dish that could use a punch of bright, tangy flavor.