Do you have excess onions that you’d like to preserve? Then this is the recipe for you! In addition to making sweet, delicious homemade onion powder, freezing roasted onions is one of our favorite ways to preserve them! When done right, it is super easy to pull out just a few roasted onions rings from the freezer as you need them for future meals. Plus, now they’re infused with that scrumptious roasted, caramelized onion flavor. Even in their frozen state, the aroma totally reminds me of fried onion rings! Yum!
In this example, we are using sweet homegrown Walla Walla onions from the garden. However, you can use any type of onion for this process! It is most ideal for processing and storage if the onions are of decent size, able to give you nice thick rings.
- Extra virgin olive oil
- Sea salt & black pepper
- Baking sheets
- Parchment paper
Step 1: Prepare the Onions
While you are preparing the onions, preheat your oven to 400°F.
As needed, wash your onions, cut away any roots and tough bottoms, and peel away the outer papery layer. Next, cut the onions into approximately 1/4 to 1/2-inch thick rounds. We like to do this across their equator, which helps them stay intact as slices of rings. Sorry, eyeballs!
Spread the onion rings out in a single layer on a baking pan lined with parchment paper. Yes, you really will appreciate the use of parchment paper here! I promise. You’ll see why in Step 3 and 4.
Next, drizzle a modest amount of olive oil over the onions, and sprinkle on salt and pepper to your liking.
As you can see, we made a double-batch!
Step 2: Roast the Onions
Roast the onions in the oven on 400°F for approximately 30 minutes, until they begin to soften and turn brown on the edges or top. If you are roasting multiple pans of onions, rotate the pans halfway through. Now sit back and enjoy that delicious aroma – as it transforms from raw, pungent onion to sweet roasted onion goodness!
Step 3: Freeze Before Packaging
Here is the key trick for this whole process – and maybe something new for you! Instead of throwing all the roasted onion slices into a package together now, we want to freeze them on their own first! When soft, warm foods are lumped together and frozen, they will do just that – lump together and freeze.
The secret to prevent frozen foods from sticking together is to freeze them individually first. This trick applies to any kind of food you are attempting to freeze, not just onions! Using this method, it is easy to take only a small portion out of the freezer to use later.
After removing them from the baking sheets from the oven, allow them to cool down at room temperature. Then, place the entire baking sheet(s) into the freezer – with the roasted onion slices still separated and not touching. Allow the onions to freeze for at least a few hours this way. We generally leave them to freeze overnight, and then package them the next day.
Step 4: Package Roasted Onions to Freeze
Now that the chunks of roasted onions have frozen on their own, you can combine them into their long-term packaging to freeze. And without sticking together! Do not allow them to defrost during the packaging process, so get all of your supplies ready before pulling the onions out the freezer.
Peel them up, and get them packed! Here is where that parchment paper really helps. Without it, the frozen onions stick to the pan like crazy, and make this transition much more messy and difficult to do quickly. We learned that the hard way!
For the best results, pack the roasted onions into an air-tight container to freeze. We like to use these BPA-free, made-in-USA reusable plastic freezer containers. They come in a variety of sizes, which we use for everything from roasted onions to soups and lentils. You could also choose to vacuum seal them. As a plastic-free alternative, you could stack the roasted onions rings in wide mouth pint or quart-size mason jars (which are freezer safe) – if your rings will fit, that is! Most of ours were too large.
Step 5: Enjoy!
Now, whenever you are out of fresh onions, pull out a couple preserved chunks from the freezer! When stored properly, roasted onions will maintain their quality in the freezer for 8 to 10 months – though they will be technically “safe” far longer! We love to chop these up to add to sautéed veggies, soups, curry lentils, or even added to the dough of homemade sourdough bread. Any recipe or meal that you’d want onions with!
Be sure to also check out our easy instructions to preserve onions by making your own onion powder. I don’t mean to make the roasted onion rings feel bad… but that stuff can’t be beat!
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Oven Roasted Onions Recipe (Freezer-Friendly)
- Roasting pan or baking sheets
- Parchment Paper
- Extra Virgin Olive Oil
- Salt and Pepper
- Preheat oven to 400 degrees Fahrenheit.
- Wash and prepare the onions by removing the outer papery layer and slicing them widthwise to create ⅛ to ¼ inch rounds.
- Place the onion rounds single layer on a baking sheet and drizzle with olive oil and a sprinkle of salt and pepper.
- Roast the onions on 400 degrees F for 30 minutes or until lightly browned.
- Once done, allow the onions and pan to cool. If you intend to freeze the onions for later use, place the cool pan of onion rounds in freezer (with the onions spread and not touching) for at least a couple hours or overnight.
- Once frozen, stack the onion rounds into an airtight container and store in the freezer until use.