Onion halves in an air fryer
Fresh — the short answer
260°C (500°F) for 5–7 min
- For
- 100g per piece, 600g in total, 6 pieces, At room temperature
- In
- Multicooker with air fry, single layer, pieces not touching
- Preheat
- Yes, before the food goes in
- Part way
- turn the pieces over at about 3 min
- Check
- The cut face is deep brown
- Safety
- Plug an air fryer directly into a wall socket. Do not run one from an extension lead. Full rule below.
Five to seven minutes, and the cut face does all the work.
Fresh
The quick answer
260°C (500°F) for 5–7 min
Onion size, for six published onions totalling 600g, peeled and halved.
- Assuming
- 100g per piece, 600g in total, 6 pieces, At room temperature
- In
- Multicooker with air fry
- Loaded
- Single layer, pieces not touching
- Preheat
- Yes, before the food goes in
- Result
- Browned but not crisp
Preparation
Peeled, halved through the root so the layers hold together, seasoned, cut side down.
How to load the basket
Single layer, pieces not touching. The reference condition. Air reaches every surface, and times are the shortest the food will achieve.
While it cooks
At about 3–4 minutes: Turn the pieces over
The cut face does all the browning; the rounded back does none.
How to tell it is done
- The cut face is deep brown
- The layers have slackened and pull apart easily
Where these figures came from — fresh
- Applies to
- Specific to this model
- Why this rating
- A published row from the manufacturer's grill chart, with the named temperature level converted to degrees using the table in the same manufacturer's instruction booklet. Both documents were read; neither figure is inferred.
- Last reviewed
- 2026-08-13
What this does not cover
- Published by the manufacturer for this appliance. It is evidence about this machine and is not general advice.
- This is a contact grill plate rather than a perforated basket. Heat reaches the food by conduction from the plate as well as by airflow, which is a different mechanism from air frying and transfers poorly to a basket machine.
Sources (1)
Ninja Foodi MAX Health Grill & Air Fryer AG551UK — Inspiration Guide and cooking charts (PDF)
SharkNinja Europe Limited — Manufacturer cooking chart (United Kingdom)
Relied on for: The temperature, time and quantity for onion halves.
States this directly
Passage read and verified
Retrieved 2026-08-13 from argos-support.co.uk
Retrieved from Argos's manual library for Argos product 735/0124, published alongside the instruction booklet as a second document.
Chilled
No time or temperature for this, and not by accident
Onion halves is sold and cooked chilled, so the question is a real one. AirfryerHQ holds no published figure for it: not one of the manufacturer manuals read for this catalogue gives a chart row for this food in this state.
We are not going to produce one by adjusting the fresh figure above. A time arrived at that way would appear on this page looking exactly like a time somebody measured, and you would have no way to tell the difference.
What we do hold for onion halves: fresh. Those are a different question, not a starting point for this one.
What usually goes wrong
A caramelised face over layers that are still raw and sharp. Heat travels badly across an onion's layers, so a large half needs longer than the chart's window or a shallower cut.
Running the appliance safely
These apply to every food and every air fryer, so they are here once rather than repeated under each state above. They come from Electrical Safety First, from UK product-safety notices and from the manufacturers’ own manuals.
- Plug an air fryer directly into a wall socket. Do not run one from an extension lead.
- An unusual smell, an unusual noise, or scorch marks on the plug mean stop using it and contact the manufacturer.
- Do not overfill. Food touching the heating element is a fire risk, not a cooking problem.
- White smoke from fatty food is usually normal. Black smoke means unplug it immediately.
- Do not leave an air fryer running unattended.
- Leave clear space above and around the appliance, and never cover the air intake or the outlet.
- Aim for a golden yellow colour or lighter on starchy foods such as chips and roast potatoes, rather than a darker brown.
- Buy from a reputable retailer rather than a third-party marketplace seller.
- Clean the drawer, the plate and the element after use. Accumulated grease is what smokes, and then what burns.
- Register the appliance with its manufacturer. It is how a recall reaches you.
- Do not rely on the appliance's own thermal protection. A UK recall was issued because it did not operate.
Each links to its own page, with what it means in practice, what to do if it has already happened, and the source it comes from. Every safety rule AirfryerHQ holds.
Why onions behaves this way
An onion is layered sheets of high-water cells separated by thin membranes, and heat travels along the layers far better than across them. A halved onion presents a large flat cut face that caramelises while the layers behind it steam in their own moisture and go sweet. A slice is mostly edge, and edges are thin, dry fast and go from caramel to bitter in about a minute — which is why the published temperature for slices is one level lower than for halves. Loose rings are also the classic food a fan lifts and throws at the element.
Where to go from here
The pages that answer the questions this one tends to raise.
- How food actually gets crispyWhy patting it dry, spacing it out and a little oil are all the same instruction — so you can apply it when a page runs out.
- Why published timings differIf another chart says something else, this is usually why — and which one to believe.
Easily confused with
- Onion slices — A different cooking problem with a different answer.