A little tangy and a little sweet, these Quick Pickled Onions are an easy and delicious way to jazz up the flavors of many of your favorite entrées, salads and side dishes.

❤️ Why You’ll Love this Pickled Red Onions Recipe

• Pickle brine gives the onions a tangy sweet flavor
• Great to use over a burger, salads, tacos and more
• Takes just a handful of ingredients
• Quick and easy to make

This recipe for sugar free pickled onions creates a bright, jewel-colored condiment that adds the prefect tangy twist to vegetables or main courses, or just enjoyed as a simple side dish.

They only take about 10 minutes to prepare without having to fuss with any canning equipment. You just slice up your red onions, cover them in a simple homemade brine and once they’ve cooled, they’re ready to serve. They’re just that easy to make!

If you love this simple pickling method, you should also check out these easy and delicious Pickled Jalapenos and these Easy Homemade Pickles.

🛒 What You’ll Need to Make Pickled Red Onions

• Red onion
• White vinegar
• Apple cider vinegar
• Water
• Monk fruit/allulose
• Kosher salt
• Peppercorns

*Exact measurements are listed in the recipe card below.

🥣 Recommended Tools

• Mandolin slicer
• Saucepan
• Whisk
• Mason jar

🔪 How to Make Quick Pickled Red Onions

Add the vinegar, water, sweetener and salt to a saucepan and heat to a simmer and whisk until dissolved.

Slice the ends off the onion, then slice in half vertically.  Slice each half into vertical very thin slices.

I used a mandolin to get very thin slices.

Tip: If you don’t have a mandolin slicer, you can use a sharp knife.

Add the onion slices and peppercorns to a mason jar.

Tip: You can also add a smashed garlic clove for added flavor.

Then pour the pickling liquid over the top and fill up the jar. 

Add the lid on and tighten to seal.

Let the onions sit at room temperature until they have cooled, about 20 minutes or so, then place them in the fridge to chill.

Once they have cooled completely, they are ready to use.

Store in the same jar in the fridge.

How Long Do Red Pickled Onions Last?

As long as you keep them chilled in the fridge in an airtight container, they will stay fresh up to two weeks. Keep in mind, the longer they sit, the softer they become.

Ways to Use Pickled Onions

• Toppings for your favorite Mexican foods like these Keto Enchiladas or on Keto Tacos.

• Replace regular onions with pickled ones on a burger with these Keto Buns.

• Add a tangy twist to Coleslaw or roasted veggies.

• Add them to any salad. They are also great added to the top of a serving of this creamy Chicken Salad.

• Chop them up and add them to Deviled Eggs.

• Save the juice and drizzle it over cooked leafy greens.

Tips for Making Pickled Onions

• Slice the onions thinly: For pickling, you’ll want to use thin slices so that the juices will soak in quickly. For best results use a sharp chef’s knife or a kitchen mandolin. You can certainly use thicker slices, but you’ll want to let them soak for a good bit longer before serving.

• Use the right types of vinegar: Vinegar is one of the main flavor profiles in this recipe, so you want to make sure you use one that taste good. Apple cider vinegar with white vinegar adds a nice flavor to the onions.

• Skip the sugar: To offset the tanginess and give the onions the perfect balance, you need to add a sweetener. But that doesn’t mean you have to load them up with sugar. I use a monk fruit/allulose blend that gives them the sweetness they need without adding extra carbs.   

• Mellow them out: If the onions you have to use are rather strong, blanch them for a couple of minutes in boiling water. Don’t leave them too long of they will become soggy.

Are Pickled Red Onions Good for Gut Health?

Onions are a good source of vitamin B9 and folate. As far as gut healthy, pickled onions are packed with probiotics and digestive enzymes.

Pickled Onion Variations

• Spice them up: If you like them extra spicy, add a few sliced fresh jalapeno or habanero peppers. 

• Garlicky onions: Garlic is good in almost anything. Add in a clove or two of thinly sliced garlic along with the onions before adding the brine.

• Herby onions: Feel free to add in fresh herbs like dill, thyme or rosemary.

• Citrus twist: Add in some fresh lemon, lime of orange zest. You can even squeeze in a little fresh citrus juice to the vinegar mixture.

• Different types of onions: Though red onions are preferred you can use white or yellow onions instead.

Are Onions Ok on Keto?

Onions, in general, are low enough in carbs, they can be enjoyed in moderation on Keto or other low carb diets. 1/4 of a red onion has about 4.9 total carbs and 3.8 grams net carbs.

More Keto Condiment and Sauce Recipes

• Bearnaise Sauce
• Easy Alfredo Sauce
• Easy Cheese Sauce for Veggies
• Bang Bang Sauce
• Buffalo Cheese Sauce
• Homemade Pesto
• Buffalo Wing Sauce