I finally nailed an Onion Strings Recipe that uses a light, seasoned batter and a one-step crisping trick that keeps things surprisingly simple.

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I never thought onion could be this addictive until I fried up a batch of crispy onion strings. I start with large yellow onions sliced so thin they almost disappear, then they turn into these crazy crunchy curls that sing when you bite them.

This Onion Strings Recipe somehow tastes fancy but it’s totally approachable, and people always ask what the secret is even though there really isnt one trick, just a few little hacks. Sometimes I toss a handful of panko breadcrumbs for extra crunch and nope, it still feels like guilty pleasure but better.

You wont be able to stop reaching in.

Ingredients

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Onions: Sweet, slightly pungent, provide fiber and natural sugars, crisp up golden when fried
All purpose flour: Creates a starchy coating, adds carbs and structure, gives a tender bite
Cornstarch: Lightens batter, makes extra crisp texture, mostly carbs, no real nutrients
Eggs: Bind ingredients, add protein and richness, help the coating stick
Buttermilk: Acid tenderizes onions, adds tangy flavor, helps batter cling, mild protein
Panko breadcrumbs (optional): Extra crunchy layer, mostly carbs, gives flaky, airy crispness when fried
Vegetable oil: Neutral frying oil, high in calories, needed for deep crisping, reuse with care
Kosher salt and pepper: Seasoning, enhances flavor, helps draw moisture from onions for crisping
Smoked paprika and cayenne: Add smoky warmth and heat, small amounts boost flavor without overpowering

Ingredient Quantities

2 large yellow onions, halved and very thinly sliced (about 12 to 16 oz)

1 1/2 cups all purpose flour

1/2 cup cornstarch

1 tsp baking powder

2 tsp kosher salt

1 tsp fresh ground black pepper

1 tsp smoked paprika

1/2 tsp cayenne pepper (optional)

1 tsp garlic powder

2 large eggs

1 cup buttermilk or 1 cup milk plus 1 tbsp lemon juice

1 cup panko breadcrumbs (optional for extra crunch)

Vegetable oil or canola oil for frying, about 2 to 3 cups

How to Make this

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1. Slice the onions very thin (use a mandoline if you got one) and separate into strings, put them in a big bowl and pour the eggs and the buttermilk (or the milk plus lemon) over them, stir so every piece is coated and let sit 10 minutes while you mix the dry stuff.

2. In another large bowl whisk together the flour, cornstarch, baking powder, 2 tsp kosher salt, black pepper, smoked paprika, cayenne (if using) and garlic powder until it’s evenly mixed.

3. Put the panko in a small shallow bowl if you want extra crunch, otherwise you can just use the seasoned flour for the second coating.

4. After the onions have soaked, working in handfuls, shake off excess wet but dont try to dry them completely, dredge the strings in the seasoned flour, shake off excess, dip them back briefly into the egg/buttermilk, then toss in the panko or back into the flour mix for a lighter crust.

5. Heat 2 to 3 cups of vegetable or canola oil in a heavy pot or deep skillet to about 350 to 375 F (175 to 190 C). Use a thermometer, it really helps.

6. Fry the onion strings in small batches so the oil temp doesnt fall,
1.5 to 3 minutes per batch depending on thickness, until golden brown and crispy. Dont overcrowd the pot.

7. Use a slotted spoon or spider to lift them out, drain on a wire rack set over a baking sheet or on paper towels, and immediately sprinkle with a little extra kosher salt while they’re hot.

8. Let the oil come back up to temp between batches, and keep fried strings warm in a low oven if you need to hold several batches.

9. Serve hot with your fave dip like ranch, spicy mayo, or ketchup. To re-crisp leftovers, spread on a sheet and bake at 350 F for 5 to 8 minutes, dont microwave or they get soggy.

Equipment Needed

1. Mandoline or a very sharp chef’s knife (for super thin onion slices)
2. Two large mixing bowls (one for soaking, one for the dry mix)
3. Whisk
4. Measuring cups and spoons
5. Shallow bowl or rimmed plate for panko or second coating
6. Heavy pot or deep skillet for frying
7. Frying thermometer (clip or instant read)
8. Slotted spoon or spider
9. Wire rack and baking sheet (rack set over the sheet for draining)
10. Long tongs and paper towels for handling and draining

FAQ

Q: How thin should I slice the onions?

A: Slice them very thin, almost paper thin, about 1-2 mm if you can. A mandoline makes this easy, or use a sharp knife and take your time. Thinner slices = crispier strings, and dont crowd the slices when you batter them.

Q: What oil and temperature should I use for frying?

A: Use a neutral oil like vegetable or canola. Heat to about 350 to 375°F (175 to 190°C). Fry in small batches so the oil temp stays steady, about 2 to 3 minutes until golden brown.

Q: Why do the recipe call for both flour and cornstarch?

A: Flour gives structure, cornstarch creates extra crispiness, and baking powder helps make the coating light. Together they give a crunchy, non-greasy finish.

Q: Can I make these ahead and reheat them?

A: Theyre best right after frying, but you can fry ahead and reheat in a 400°F oven or air fryer for 3 to 6 minutes to crisp them up. Store cooled rings in a single layer in the fridge for up to 24 hours.

Q: Any tips to keep them crispy?

A: Drain on a wire rack not directly on paper towel if you can, salt right after frying, dont stack the strings, and keep them in a warm oven (about 200°F) if you need to hold them a short time. Serve asap for best crunch.

Q: Can I make substitutions for gluten or eggs?

A: Yes. For gluten free use a 1:1 GF flour blend and GF panko or extra cornstarch. For egg free try a flax egg or 3 tablespoons aquafaba as a binder, but the coating may be a little less airy. Adjust and test one batch first.

Fried Crispy Onion Strings Recipe Substitutions and Variations

Buttermilk: 1 cup plain yogurt thinned with 2 to 3 tbsp water (same tang); or 1 cup milk + 1 tbsp lemon juice or vinegar; or 1 cup unsweetened soy or oat milk + 1 tbsp lemon juice if you want dairy free.
Eggs: for 2 eggs use 2 tbsp ground flaxseed + 6 tbsp water (mix, wait 5 min) as a binder; or 6 tbsp aquafaba (chickpea liquid); or a commercial egg replacer following package amounts.
All purpose flour: 1-to-1 gluten free flour blend; or mix chickpea flour with a bit of rice flour for crispness (chickpea alone has a strong taste); or whole wheat pastry flour for a nuttier note.
Panko breadcrumbs: crushed cornflakes or crushed potato chips for extra crunch; or regular breadcrumbs toasted; or just skip them and add a bit more flour + cornstarch for a lighter crisp.

Pro Tips

1) Use a mandoline for super thin slices if you got one, but dont be dumb with it. Wear a cut-resistant glove or use the guard, or just use a very sharp knife and take your time. Thin even strings fry faster and crisp up way better.

2) Keep the batter and coated onions cold for a few minutes before frying, it helps the crust set and stops the oil from soaking in. Also, mix the flour with the cornstarch and baking powder real well, and season both the flour and the panko so every bite has flavor.

3) Oil temperature is everything, so use a thermometer and keep it between 350 and 375 F. Fry in small batches so the temp doesnt crash, and wait for it to come back up between batches, otherwise you get greasy limp strings.

4) Drain on a wire rack not just paper towels, sprinkle kosher salt the second they come out, and if you need to hold them keep them in a single layer in a 200 F oven. To re-crisp leftovers bake at 350 F for 5 to 8 minutes, dont microwave or they get soggy.