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    Home » Pickled Vegetables

    Balsamic Vinegar Pickled Onions

    April 10, 2023 by cookingwithelo Leave a Comment This post may contain affiliate links.

    Jump to Recipe Jump to Video

    Think pickled red onions but with a Mediterranean twist! These balsamic vinegar pickled onions are going to become your new favorite things to add to Mediterranean salads, sandwiches, and grilled summer vegetables.

    Fork with balsamic vinegar pickled red onion slices.

    Balsamic vinegar is naturally sweeter than red wine vinegar or white vinegar, which makes it the perfect choice for pickled onions. While its dark color may scare some people off, the onions look bright pink once they are out of the brine.

    This recipe combines the flavors of a classic balsamic vinegar dressing with the pungent taste of red onions. If you like it, make sure to also give these red wine vinegar pickled onions and these pickled yellow onions with dill and mustard seeds a try.

    Jump to:
    • What is quick pickling?
    • Key ingredients and substitutions
    • Elo's tips
    • Step-by-step instructions (with pictures)
    • How to serve balsamic vinegar pickled onions
    • Frequently asked questions
    • The recipe

    What is quick pickling?

    Unlike fermentation, quick pickling uses vinegar and sugar to pickled onions and other vegetables (such as these pickled carrots or this pickled cauliflower). In this case, the sliced onions are soaked in a sweetened vinegar and water mixture and stored in the refrigerator for up to 2 weeks – hence why they are sometimes called refrigerator pickles.

    Key ingredients and substitutions

    Ingredients for balsamic wine vinegar pickled onions in small jars.
    • Red onions: they are my go-to onion variety as they pair really well with balsamic vinegar and Mediterranean recipes.
    • Balsamic vinegar: I like to use high-quality balsamic vinegar, preferably made with minimal ingredients and without flavorings. You can substitute it with apple cider vinegar, which has a similar amount of sweetness, or check out this red wine vinegar pickled onions recipe.
    • Sugar: balances out the tartness of the vinegar.
    • Salt: increases the preservation time of the pickled onions.
    • Spices: add a ton of flavor. To keep it simple, simply add black peppercorns and oregano or Italian herbs. You can also add fennel seeds for an anise flavor, and red pepper flakes for some heat.
    • Fresh herbs: I LOVE adding fresh herbs to my pickled onions. Fresh thyme or rosemary would pair really well with the other flavors of this recipe.

    Elo's tips

    1. Prepare the brine in the microwave to save time. Make sure the brine is hot and the salt and sugar have dissolved.
    2. Use 16-ounces (500 ml) Weck or Mason jars. They have the perfect size to fit 2 medium-sized red onions or 3-4 small ones.
    3. This recipe gets even better over time, so don't feel rushed to eat them all right away.

    Step-by-step instructions (with pictures)

    Balsamic vinegar brine in a small saucepan.

    STEP 1: Prepare the balsamic vinegar brine. Add the water, vinegar, salt, and sugar to a small saucepan. Simmer until salt and sugar have completely dissolved.

    Sliced red onions on a wooden cutting board.

    STEP 2: Slice onions very thinly with a sharp knife of a mandoline.

    Sliced red onions in a glass jar.

    STEP 3: Add the onion slices to a clean glass jar. My go-to is this 16-ounce (500 ml) Weck jar.

    Sliced red onions in balsamic vinegar brine in a glass jar.

    STEP 4: Pour the warm vinegar mixture on top. Make sure the onions are completely covered and leave about ½ inch (1 cm) room at the top.

    Hand holding a small plate with spices above a jar with red onions in vinegar brine.

    STEP 5: Add in the dry spices. Give everything a good stir. Wipe off the rim of the jar and close it with a lid.

    Sliced red onions in balsamic vinegar brine with spices in a glass jar.

    STEP 6: Let it cool on the counter until it reaches room temperature. Then, place it in the refrigerator for at least 20 minutes or preferably overnight.

    How to serve balsamic vinegar pickled onions

    • As a salad topping: they would go really well with this Mediterranean tomato and cucumber salad.
    • On a sandwich: think about a generously filled grilled vegetable sandwich.
    • In a wrap: check out this vegan pesto wrap.
    • On a pizza: this lemony white sauce pizza with spinach could really benefit from pickled red onions.

    Frequently asked questions

    How to store quick pickled red onions?

    You can keep the pickled onions in the refrigerator for 2 weeks. Make sure the onions are completely submerged in vinegar brine the entire time.

    How do I know if the onions have gone bad?

    If the onions look or feel slimy, it's preferable to throw them out. If some pieces were not submerged in pickling liquid, they may have gone bad as well.

    Fork with balsamic vinegar pickled red onion slices.

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    The recipe

    Fork taking balsamic vinegar pickled red onions from a jar.

    Balsamic Vinegar Pickled Onions

    5 from 1 vote
    These balsamic vinegar pickled onions taste like traditional pickled red onions with a Mediterranean twist. They are amazing on salads and wraps.
    Print Pin
    Prep Time: 5 minutes minutes
    Cook Time: 5 minutes minutes
    Total Time: 10 minutes minutes
    Servings: 4
    Author: Eloïse Jennes

    Equipment

    • 16-ounces Weck jars 500 ml

    Ingredients 

    • 2 medium red onions

    For the vinegar brine

    • ⅔ cup (160 ml) balsamic vinegar
    • ⅔ cup (160 ml) water
    • 1 tablespoon sugar
    • ½ teaspoon salt

    Herbs and spices

    • 1 teaspoon dried oregano
    • ¼ teaspoon black peppercorns
    • ¼ teaspoon fennel seeds optional
    • ¼ teaspoon red pepper flakes optional
    • 1 sprig fresh oregano optional

    Instructions

    • Add the balsamic vinegar, water, salt, and sugar to a small saucepan. Heat over medium heat until the salt and sugar have completely dissolved.
    • Slice the red onion very thinly with a sharp knife or a mandoline.
    • Add the sliced onions, dried oregano, black peppercorns, fennel seeds, red pepper flakes, and fresh oregano (if using) to a clean glass jar. Pour the warm vinegar brine on top and close the jar with a lid. Let it come to room temperature.
    • Place in the refrigerator overnight or at least 20 minutes before serving.

    Video

    Notes

    1. You can store these pickled onions in the refrigerator in an airtight container for 14 days.
    2. Use on salads, such as this Mediterranean tomato cucumber salad, sandwiches, and wraps.
    3. Always make sure the onions are completely covered in vinegar brine. Onion pieces that were not submerged in vinegar are prone to bacterial growth.
    4. If they feel slimy or if some onions were not covered with pickling liquid, it's best to throw them out. 

    Nutrition

    Calories: 63kcal | Carbohydrates: 13g | Protein: 1g | Fat: 0.1g | Fiber: 1g | Sugar: 11g
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