Slice the Onion: Peel a small red onion, then cut it in half from top to bottom through the stem. Place the halves flat-side down on a cutting board and slice into 1/4-inch thick pieces. Transfer the slices to a 2-cup mason jar. Avoid metal or plastic containers—metal can react with vinegar, and plastic may absorb flavors.
Make the Pickling Liquid: In a small saucepan, combine water, vinegar, lime juice, honey, and salt. Heat over medium-high, stirring occasionally. Once the honey dissolves and the mixture starts to simmer, remove it from the heat.
Add the Brine: Let the liquid cool slightly, then slowly pour it over the onions in the jar to prevent the glass from cracking. Use a spoon to press the onions down so they’re fully submerged.
Let It Sit & Store: Cover the jar and let the onions sit at room temperature for 30 minutes before refrigerating. This recipe makes about 2/3 cup (70 grams) of pickled onions.Pro Tip: Pickled onions taste even better after a day or two in the fridge. Keep them sealed in an airtight jar for the best flavor.
Notes
Pick the Right Vinegar: Vinegar affects the flavor of your pickled onions. Apple cider vinegar and white vinegar are great choices, but you can also try red wine or rice vinegar for a different taste. Avoid balsamic or malt vinegar, as their flavors can be too strong.
Customize the Flavor: This is a basic pickled onion recipe, but you can add spices to suit your taste. Try peppercorns, mustard seeds, bay leaves, red pepper flakes for heat, fennel seeds for a slight anise note, or a pinch of cumin for earthiness. Adjust the sugar and salt to your liking.
Slice to the Right Thickness: Cut onions into 1/4-inch slices—thin enough to soften in the brine but thick enough to hold their texture.
Use a Proper Jar: Since these onions aren’t heat-processed, you don’t need a canning jar. A 2-cup (1-pint) mason jar or any glass container with a lid works well.
Keep It Clean: Wash and dry your jar thoroughly before using it to prevent introducing bacteria into the brine.