The Easiest Homemade Onion Infused Olive Oil

Onions are one of those staple ingredients that quietly carry a ton of flavor and health benefits. Turning them into a homemade infused oil is super simple and a great way to add a sweet and savoury depth to tons of dishes, without needing to chop an onion every time.

Before we jump into the how-to, here are a few great reasons to keep onion-infused oil in your kitchen:

• Supports digestion: Especially when made with a low FODMAP diet in mind.
  
• Rich in antioxidants: Onions are full of compounds that help fight inflammation.
  
• Adds flavour fast: No need to sauté every time—just drizzle and go.
  
• Versatile ingredient: Works in salad dressings, pasta sauces, or over roasted veggies.
  
• Customisable: Add other natural ingredients like garlic oil, herbaceous cilantro, or a dash of grapefruit white balsamic for variation.
  

What you need

Supplies

1 large yellow onion (or red onions for a slightly different flavor)

1 cup ultra premium certified extra virgin olive oil – I buy this bulk source

Tools

A clean glass jar – I usually use these pint mason jars

Cheesecloth or fine mesh strainer – Here is a source for extra large unbleached cheesecloth

Knife

How to make onion-infused oil

Peel and chop your onion into smaller pieces—the smaller, the better for even cooking and flavor release.

In a small saucepan, add your base oil (I recommend olive oil) and onion pieces. Keep it on low heat—you don’t want to fry the onions. You’re aiming for a gentle infusion process where the warm oil gently extracts the flavour of the onions.

Let the mixture warm very gently for about 20–30 minutes. The onions should look golden but not burnt. You’ll notice the onion aroma getting stronger.

Turn off the heat and allow the oil to cool to room temperature. 

Pour the oil through a cheesecloth or strainer into your jar, catching all the solid bits. You want a clean, clear oil to avoid spoilage. 

Make sure to date and label the oil so you remember what it is and when you made it. That’s it!

How long does onion-infused oil last?

Keep your finished oil in a sealed container in a cool dark place (I store mine in the fridge) and use it within 1–2 weeks.

Ways to use onion-infused oil

You can use this oil in a wide range of dishes.

• Toss with roasted veggies like carrots, squash, or potatoes to amplify the subtle sweetness of the veg.
  
• Drizzle over grilled bread with feta cheese and tomatoes.
  
• Use in homemade salad dressings with a splash of sicilian lemon white balsamic or honey ginger white balsamic vinegar.
  
• Mix into savoury dishes like stir-fry or rice bowls to add the sweet flavor of onions.
  
• Try it in place of highly processed vegetable oil in your next marinade.

How to decrease the risk of botulism in infused oils

Botulism is caused by Clostridium botulinum, a bacteria that thrives in low-oxygen, low-acid, and room-temperature environments—exactly like oil. But you can still safely enjoy homemade infusions with a few precautions:

• Always strain out solids: After infusing, strain the oil thoroughly using cheesecloth or a fine mesh strainer. Any bits of onion or garlic left behind can harbor bacteria. 
• Refrigerate the oil: Store your infused oil in the fridge.
• Use within 1–2 weeks: Homemade infused oils don’t have preservatives, so they’re not meant for long-term storage. 
• Use sterile containers: Wash your jars or bottles with hot soapy water and let them air dry completely before pouring in your oil.
• Use heat to infuse the oil: Infusing over low heat helps kill off surface bacteria. Let the onions gently heat and infuse for at least 20–30 minutes.

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