Roasted red onions are such an underrated side to any dish or for meal prep! Baking the onions in the oven gives it a delicious crispy texture packed with flavor, making it a great salad, taco or sandwich topper, or a standalone side! Best yet, it's ready in 30 minutes!
The post contains helpful tips and tricks to make sure you're successful in your first attempt. But if you're in a rush, please use the link above to jump to the recipe card at the end!
💭 Why you'll love this recipe
- Ready in 30 minutes: This recipe only requires about 5 minutes of active prep time, and comes together in just 30 minutes total!
- Super versatile: I love adding these roasted red onions to tacos, sandwiches, or salads. They taste great on my fried avocado tacos and on my Korean street toast sandwich!
- Needs just four ingredients: Can this recipe get any better? Of course, there are a bunch of toppings and seasonings you can add but you really just need onions, neutral cooking oil, salt and pepper for the most crispy and flavorful onions!
📋 Ingredients and notes
You'll need a large red onion, about a tablespoon of neutral cooking oil (I use avocado oil) and then salt and pepper.
Notes and Variations
- Other types of onions: I prefer red onions since they're sweet and caramelize well. I've tried them with mild yellow onions before and they tasted okay, but I preferred the red onions. I recommend not using white or Vidalia onions since they are quite pungent!
- Types of cooking oil: I prefer avocado oil as a base oil for many recipes because it's neutral flavored and has a high smoke point! You could use olive oil as well, but in that case, I'd suggest lowering your oven temperature to 375F and cooking a bit longer instead of roasting at 400F as written in the recipe. Notes provided in the recipe card!
📖 How to make easy roasted red onions
Slice the onion into thin rounds
Wash and cut off the root edges of the onion, and peel the skin. First, cut the onion into two halves. Then, slice each half into a series of circular onion slices.
Preheat oven to 400F and season the onion
Preheat your oven to 400F. Then, lay out the onions in a thin layer in an oven proof baking dish (or better yet, a nice enameled cast iron braiser or skillet!) Drizzle olive oil, and top with salt and pepper. Toss the onion rings and spread them out so they're well seasoned.
Bake in the oven for 20 minutes
Place the baking dish in the oven and roast / bake for 10 minutes first. Then take the skillet out carefully using oven mitts, and then toss them a bit more (or flip them).
You can skip this step and cook the full 20 minutes as well, but I prefer taking them out halfway since I find this browns the two sides evenly! Cook until the onion rings are nicely caramelized, crispy on the outside, but tender to bite. Your roasted red onions are ready!
👩🏽🍳Top tips and FAQs
Adding about half a tablespoon of balsamic vinegar can make the onions caramelize faster because of the sugar content! This makes great balsamic roasted red onions!
I prefer red onions, and mild-flavored yellow onions also work. But I try to avoid white onions and Vidalia onions since I find them quite strong!
Seriously, this is a great topping for any taco, sandwich, or salad. I've added these to my fried avocado tacos and gochujang cauliflower tacos in lieu of pickled onions, added them to a delicious roasted beet salad and sometimes just eat them straight!
🍴 Serving and storage suggestions
Roasted red onions are good in the fridge in an airtight container for at least a couple of days. You can either reheat them in a microwave or if you want to preserve the crispiness, throw them on a skillet to warm up (or add them on top of scrambled eggs!) Sometimes I add them to my crispy kimchi pancakes for a fun, Korean-inspired breakfast!
If you like this recipe, don't forget to try out my other easy and healthy sides recipes:
To find out other recipes that are in season, check out my seasonal produce guides!
Roasted Red Onions
- 1 red onion, large, sliced into thin circles
- 1 tablespoon avocado oil
- 1 teaspoon kosher salt
- ½ teaspoon crushed black pepper
- ½ teaspoon garlic powder
- Wash and peel one large red onion. Slice off the root edges, and cut them into two halves. Then, slice each half into ¼-inch thick slices. Use your fingers or a fork to separate the slices into thin rings.
- Preheat the oven to 400°F. While the oven is heating, spread the onion slices / rings evenly, neatly spaced out in an oven-proof baking dish or a cast iron skillet. Toss the slices with avocado oil, and toss to coat. Then, add a teaspoon of salt, and ½ teaspoon each of black pepper and garlic powder and use your hands or a fork to toss them and spread them out evenly.
- Roast the onions for about 10 minutes. Then, stir once and then continue roasting for another 10 or so minutes, until the onions are tender and caramelized, and starting to get crispy on the sides! Serve as a side or snack!
- You can also use a mild yellow onion in this recipe but I prefer using a red onion since it turns out sweeter when caramelized!
- I prefer using avocado oil since it has a high smoke point and can withstand 400F oven temperatures without smoking. Olive oil works fine in the recipe if you reduce the temperature of the oven to 375F and roast for 25 to 30 minutes instead!
- You can use a glass or ceramic baking dish or a cast iron skillet. I find that using a cast iron skillet creates crispier edges, but make sure to use an enameled one or ensure that the bottom is coated in a thin layer of oil to prevent any sticking!