Super thin crispy fried onions are fabulous all by themselves to munch on, but try using them to top a casserole and you’ll have everyone asking for more. Light and crispy and easy to make, the secret ingredient is buttermilk.
Make extra, there’s never enough!

Crispy fried onions are so easy to make and great to have on hand to add to your favorite side dishes, especially during the Holidays. My family is always thrilled when they hear I’m making a batch. They can’t resist the golden crispy texture. While I love them by themselves, they’ll add that little bit of extra to a dish.
I don’t fry too many things, but seriously crispy onions are worth the extra calories. I would actually say these are more sautéed then fried. Even if frying isn’t your thing, I would encourage you to experiment just a bit and give these a try.
I generally have some extra onions and buttermilk hanging around. If not, what’s another trip to the grocery. You can always put onions to use. This recipe uses buttermilk but if you only have milk, add a tablespoon of lemon juice or vinegar to a cup of milk and let it sit for a few minutes until it thickens slightly.
I tried these the first time to put on my Green Bean Casserole at Thanksgiving instead of French’s. They were so addicting, that I almost didn’t have enough to put on the casserole. Every time someone passed through the kitchen they would grab a handful. Somehow they aren’t greasy even though they’re fried.
When adding to the top of a casserole, since they are already cooked, wait until the last few minutes before adding them. You just want to warm them up.
Why you’ll love crispy onion strings
- They are simple to make but taste oh so good, better than the store bought version!
- The added texture to foods takes them one step up in flavor.
- Even though they are fried, they don’t come out greasy.
- They make a great topping on a casserole, sandwiches, salads and burgers.
What you’ll need
- Onions – use two large sweet onions. Yellow will work as well.
- Buttermilk – In a pinch you can make your own buttermilk with milk and lemon juice or white vinegar.
- Salt – add according to your own taste. You’ll add this at the end when they’re hot.
- Flour, vegetable oil
How do you make crispy fried onions
Step 1: Cut the onions in half and with a mandolin slice into very thin slices.
Place in a bowl and pour buttermilk over the top. Let them sit in the buttermilk for 15 minutes. Drain well.
Step 2: Toss onions with flour and shake off excess. If you enjoy a little spice, you can add some cajun seasoning into the flour to give it a bit of seasoning – you just need a tablespoon.
Step 3: Bring about ¼ inch of vegetable oil to 300º over medium heat in a heavy skillet. Add onions and cook until golden brown, about 7-9 minutes. Turn and brown the other side. Remove to a paper towel lined plate and immediately salt. Don’t be tempted to turn up the heat, let them cook slowly.
Don’t add too many onions to the pan, just let them cover the bottom and cook them in batches, adding more oil if needed.
Don’t let the oil get too hot. The onions will cook too fast and you won’t get that beautiful golden color.
Pro tip: I thought these would be hard to make or at least a lot of trouble but they’re not. I used a mandolin to cut the onions, this is a must unless you have really good knife skills. If you don’t have a mandolin, you should add it to your list, I use mine for so many things, recently for an Apple Pear Galette.
Crispy onions are perfect eaten alone and not nearly as heavy as french fries or regular onion rings.
How to enjoy onion strings
- Add these to any casserole that you might top with bread crumbs or Ritz crackers for a crunchy topping that will be a show stopper, like broccoli cheese casserole. Meatloaf, mac & cheese or veggies will be better for it.
- You can add a sprinkling to a salad or as a burger topping!
- They add a delicious flavor to soups too, like this zesty chicken soup!
- I’ve heard they make a great sweet and salty addition if you top a milkshake with a couple of strings. If you try it, let me know what you think!
I hope these jazz up your holiday meal this year.
FAQs and tips
Sweet onions are a milder onion because they contain less sulfur and more water. Great for stuffing and onion rings, and even enjoying raw, these are one option. Yellow onions, also known as brown onions, are always a great onion for cooking and baking. They become mellow in flavor when you caramelize or saute them.
Yes, these will stay fresh for a day or two. If using later, freeze them and add to the casserole at the end of the cooking time. They are delicious at room temperature since they aren’t greasy.
Yes, these root vegetables have health benefits. You will be glad to know they are high in antioxidants and are linked to improve bone health and lower blood sugar levels. They contain sulfur compounds which help reduce cholesterol levels.
When you cut into an onion, an enzyme is released and your body secrete’s tears to wash it away.
Yes, you can freeze onions. If you prefer to cut them up, know they tend to lose their shape when they thaw so determine if you want them a certain size ahead of time.
Yummy side dishes to enjoy
If you loved this recipe, give it a star ⭐️⭐️⭐️⭐️⭐️ rating! Also, snap a picture of your finished dish and share it with me on Instagram using the hashtag #butterandbaggage and tagging me @butterandbaggage.
Crispy Fried Onions
Ingredients
- 2 large onions
- 1 cup buttermilk
- 1 cup flour
- vegetable oil for frying
- salt to taste
Equipment
Instructions
- Cut onion in half and with a mandolin slice into very thin slices. Place in a bowl and pour buttermilk over the top. Let them sit in the buttermilk for 15 minutes. Drain well.
- Toss onions with flour and shake off excess.
- Bring about ¼ inch of vegetable oil to 300º over medium heat in a heavy skillet. Add onions and cook until golden brown, about 7-9 minutes. Turn and brown the other side. Remove to a paper towel lined plate and immediately salt.
Barbara’s Tips + Notes
- Unless your knife skills are excellent, a mandolin will help you achieve the uniform size and thinness of onions you want for this recipe. If you invest in one, you’ll have a lot of great recipes to get use of it on!
- Toss in a tablespoon of cajun seasoning to the flour before dredging the onions in for extra kick.
- A cast iron works great for frying if you don’t have a dedicated fryer.
- If you have lots of onions, you may have to cook half at a time.
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