Balsamic Pickled Onions

A glass jar filled with pickled red onions in vinegar brine. The jar is set on a blue and white coaster, with a light napkin nearby and a sliced onion in the background.

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Quick, tangy-sweet balsamic pickled onions made with simple pantry ingredients—ready in 30 minutes and perfect for adding bold flavor to tacos, salads, wraps, and more.

Prep Time5

Resting Time25

Total Time30

Course: Condiment

Cuisine: American, Asian

Diet: Vegan

Servings: tablespoon

Calories: 13kcal

Author: Hawwa

Equipment

1 Mandoline slicer

Ingredients

1 Large Red Onion
2 Cloves Garlic
¾ Cup Balsamic Vinegar
¾ Cup Water
3 tablespoon Maple Syrup
½ teaspoon Kosher Salt
1 teaspoon Black Peppercorns
1 teaspoon Dried Rosemary

Instructions

Thinly slice red onion (about ⅛-inch) and garlic.
In a small saucepan, combine balsamic vinegar, water, maple syrup, salt, peppercorns, and rosemary. Heat over medium. Stir and bring to a gentle simmer, not a boil. This takes about 3–4 minutes, just until the salt dissolves and flavors open up.
Add onions and garlic to a clean glass jar. Pack them snugly. They will soften and shrink slightly once the hot brine is added.
Pour hot brine over, fully covering.
Cool & chill 20–30 mins, then refrigerate. Best after overnight.

Notes

Use a good-quality balsamic vinegar. This is the backbone of the recipe, so it matters. You don't need anything aged or expensive, but avoid the very thin, watery varieties. A mid-range balsamic with some body will give you the best results.
Maple syrup is key — don't substitute sugar. Maple syrup adds a rounded, caramel-like sweetness that granulated sugar can't replicate. It also integrates seamlessly into the brine without needing extra time to dissolve.
Slice consistently. A mandoline slicer makes this much easier if you have one, but a sharp knife works perfectly fine. Just take your time.
Let them rest. Thirty minutes will give you a decent pickle. A few hours will give you something great. Overnight will give you something spectacular.
Don't skip the garlic. The thinly sliced garlic pickles are right alongside the onion and add an incredible depth of flavor to the finished product.

Nutrition