Air Fried Crispy Onions

Some toppings are nice. Some toppings completely transform the dish they land on. These air fried crispy onions are firmly in the second category — light, golden, shatteringly crunchy, and so deeply flavorful that they make everything they touch genuinely better. Paper-thin onion strands tossed in a whisper of oil and cornstarch and air fried until deeply golden and irresistibly crispy. Ready in just 27 minutes with almost no oil and seven simple ingredients. These are the homemade crispy onions that make store-bought versions feel completely unnecessary.

Perfect on burgers, casseroles, salads, soups, baked potatoes, and virtually anything else that could use a genuinely spectacular crunchy topping. Make a batch and find yourself putting them on everything for the rest of the week.

Why You’ll Make This Again

The cornstarch is the professional technique that makes these crispy onions so extraordinarily light and crunchy. It absorbs any surface moisture from the raw onion slices and creates a thin, airy coating that crisps dramatically in the air fryer without requiring deep frying or significant oil. The two-stage temperature approach — starting lower to dehydrate the onions gently and then finishing hotter to achieve that deep golden crunch — produces a result that genuinely rivals restaurant-quality crispy onions. And the fact that the entire batch uses just one tablespoon of oil and clocks in at only 60 calories per serving makes these the crispy, crunchy topping that you can scatter generously over everything without a second thought. These are a complete game changer.

These work beautifully all year round as a versatile topping but are especially wonderful for holiday green bean casserole, Thanksgiving spreads, summer burger nights, and any occasion where you want something that genuinely elevates every dish it touches.

How This Comes Together

Slice the onions paper thin, toss in oil, coat in cornstarch, and air fry in two temperature stages with regular shaking until deeply golden and perfectly crispy. The entire process takes just 27 minutes with only a few minutes of hands-on prep. The most important step is slicing the onions as thin as possible — 1/8 inch or thinner is the target thickness that produces crispy, delicate onion strands rather than thick, chewy pieces that never fully crisp up even with the right technique. A mandoline makes this completely effortless and is strongly recommended for the most consistently thin and even slices.

What You’ll Need

Seven simple ingredients. Use sweet onions — Vidalia or Walla Walla — for the most naturally mild, slightly caramelized crispy onions with a gentle sweetness that works beautifully on any dish.

• 2 large yellow or sweet onions, thinly sliced (about 1 lb)
• 1 tbsp neutral cooking oil (avocado, canola, or light olive oil)
• 1 tbsp cornstarch or rice flour
• 1/2 tsp fine sea salt
• 1/4 tsp garlic powder (optional)
• 1/4 tsp smoked paprika (optional)
• Pinch of cayenne pepper (optional)

Step-by-Step Directions

Step 1: Prepare the Onions

Peel the onions and slice them paper-thin, approximately 1/8 inch thick. Separate all the slices into individual rings or strands.

Place the sliced onions in a large bowl. Drizzle with the oil and toss until every piece is evenly and lightly coated.

Step 2: Coat the Onions

Sprinkle the cornstarch or rice flour over the oiled onions. Toss thoroughly until every piece is lightly and evenly coated, with no visible dry clumps of starch remaining.

Step 3: Air Fry the Onions

Preheat the air fryer to 325°F (165°C) for 2 minutes.

Arrange the coated onions in an even layer in the air fryer basket.

Air fry at 325°F for 10 minutes, shaking the basket every 3–4 minutes to promote even cooking and browning.

Step 4: Crisp and Finish

Increase the temperature to 350°F (175°C) and continue cooking for 5–7 minutes, shaking the basket every 2 minutes, until the onions are deep golden brown and crispy throughout.

Immediately transfer the onions to a paper towel-lined plate or baking sheet. Sprinkle with fine sea salt and any optional seasonings while still hot.

Allow the onions to cool for 3–5 minutes so they crisp up completely before serving or storing.

How to Serve It

Scatter the cooled crispy onions generously over whatever dish you are serving them with — the more the better. They are transformative on a classic burger where they add crunch, sweetness, and depth to every bite — but they are equally spectacular scattered over a bowl of French onion soup, piled on top of a baked potato with sour cream, stirred through a green salad for unexpected texture, or used as a topping for the classic green bean casserole at Thanksgiving. Store in a wide-mouth jar or airtight container on the counter and reach for them as a finishing touch on virtually any savory dish throughout the week. For a complete burger night, serve alongside our Baked Garlic Parmesan Potato Wedges for an irresistible combination that elevates the entire meal.

Leftovers & Storage

Store completely cooled crispy onions in an airtight container or glass jar at room temperature for up to 5 days. Make sure they are completely cool and fully crispy before sealing — any residual warmth creates moisture inside the container and softens the onions within hours. If they lose their crunch after a day or two, spread on a baking sheet and return to a 350°F oven or air fryer for 3 to 4 minutes to re-crisp completely — they come back beautifully with just a few minutes of gentle heat. These do not freeze well as the texture changes significantly after thawing. A fresh batch takes just 27 minutes so making them fresh whenever needed is always the best approach.

Make It Even Better (Pro Tips)

• Use a mandoline slicer for the most consistent, paper-thin slices — inconsistent thickness means some pieces crisp perfectly while others stay chewy or burn in the same cook time.
• Separate every onion slice into individual strands before tossing — clumped slices that stay together during cooking never crisp evenly and produce soft, steamed patches in the finished batch.
• Use just enough oil to lightly coat — too much oil makes the onions greasy and prevents them from crisping properly. One tablespoon for a full pound of onions is the right ratio.
• Shake the basket frequently — every 2 to 3 minutes throughout both stages of cooking ensures even browning and prevents any pieces from burning while others are still pale.
• Never walk away during the final 5 to 7 minutes at 350°F — the onions can go from perfectly golden to burned very quickly at the higher temperature. Stay close and shake frequently.
• Season with salt immediately after removing from the air fryer — salt adheres far better to hot crispy onions than to cooled ones and distributes more evenly throughout the batch.
• Cool completely on a wire rack or paper towel-lined surface before storing — cooling on a flat surface with air circulation is what allows any remaining steam to escape and the onions to achieve their maximum crispiness.

Easy Ways to Change It Up

• Everything bagel seasoning: Replace the individual optional seasonings with everything bagel seasoning for a bold, complex flavor combination that makes these crispy onions taste incredible on avocado toast, salads, and soups.
• Ranch seasoning: Toss with a teaspoon of dry ranch seasoning mix along with the cornstarch for a tangy, herbaceous crispy onion that is completely addictive on burgers and baked potatoes.
• Spicy version: Double the cayenne and add a teaspoon of chili powder for crispy onions with a serious warming heat that pairs beautifully with cool sour cream or yogurt-based dips and toppings.
• Parmesan version: Toss with a tablespoon of finely grated Parmesan along with the cornstarch before air frying for a richer, more deeply savory crispy onion that is extraordinary on pasta and salads.
• Red onion version: Use red onions instead of yellow or sweet onions for a slightly earthier, more peppery crispy onion with beautiful purple-tinged color that looks stunning scattered over any light-colored dish.

Quick Questions

Can I use rice flour instead of cornstarch?

Yes — rice flour is an excellent substitute and actually produces an even lighter, more delicate crunch than cornstarch in some air fryers. It is also naturally gluten-free, making it the preferred choice for anyone avoiding gluten. Use the same quantity — one tablespoon — as a direct one-for-one substitution and the technique and result will be virtually identical to the cornstarch version.

Why are my crispy onions soft instead of crunchy?

Three most common causes — the onions were sliced too thick, the air fryer basket was overcrowded preventing proper air circulation, or the onions were sealed in a container before cooling completely. Always slice as thin as possible, work in batches if needed to avoid overcrowding, and allow the onions to cool completely and reach their maximum crispiness before storing or serving. The onions continue to crisp for 3 to 5 minutes after removing from the heat so patience in the cooling stage is essential.

Can I make these in the oven instead of the air fryer?

Yes — spread the coated onions in a single layer on a parchment-lined baking sheet and bake at 375°F for 20 to 25 minutes, stirring every 5 to 7 minutes, until deeply golden and crispy. The oven takes slightly longer and requires more frequent stirring than the air fryer but produces an excellent result. Watch closely in the final 5 minutes as the onions can go from golden to burned quickly at this temperature.

Make these air fried crispy onions this week and discover the homemade topping that makes everything it touches genuinely better. Tried them? Leave a comment below and tell me what dish you used them on first! — Ava