Onions cooking times
How long to cook onions: 8–10 min pan-fried, 30–40 min in the oven at 200°C (180°C fan), 10–12 min in an air fryer at 190°C and 2–3 min deep-fried at 180°C. Every way to cook it is below, with the temperature and how to tell it’s done.
How long to cook onions
Times are for 2 large onions, for 4.
| Method | Time | Heat | How |
|---|---|---|---|
| Pan-fry Softened | 8–10 min | over a medium heat | Fry in oil or butter, stirring often, until soft and translucent. |
| Pan-fry Caramelised | 35–45 min | over a low heat | Caramelised: cook slowly in butter and oil, stirring every few minutes, until deep golden. It can’t be rushed. |
| Oven Wedges | 30–40 min | 200°C (180°C fan), 400°F, gas 6 | Wedges tossed in oil. |
| Air fryer Wedges | 10–12 min | 190°C (375°F) | Wedges or thick slices, tossed in a teaspoon of oil. |
| Deep-fry Rings | 2–3 min | oil at 180°C (350°F) | Onion rings, battered or floured. |
| Barbecue Thick slices | 8–10 min | over medium direct heat | Thick slices brushed with oil; turn once. |
| Microwave Softened | 4–5 min | on full power | Sliced, with a knob of butter, to soften quickly before frying. |
Before you start
Peel, halve and slice, or cut into wedges through the root so they hold together.
How to tell it’s done
Softened onions are translucent and floppy with no colour; caramelised onions are deep brown, sticky and sweet.
Questions
How long to pan-fry onions?
Softened: 8–10 min over a medium heat. Fry in oil or butter, stirring often, until soft and translucent. Caramelised: 35–45 min over a low heat. Caramelised: cook slowly in butter and oil, stirring every few minutes, until deep golden. It can’t be rushed.
How long to cook onions in the oven?
Wedges: 30–40 min at 200°C (180°C fan), 400°F, gas 6. Wedges tossed in oil.
How long to cook onions in an air fryer?
Wedges: 10–12 min at 190°C (375°F). Wedges or thick slices, tossed in a teaspoon of oil.
How long to deep-fry onions?
Rings: 2–3 min in oil at 180°C (350°F). Onion rings, battered or floured.
How long to barbecue onions?
Thick slices: 8–10 min over medium direct heat. Thick slices brushed with oil; turn once.
How long to microwave onions?
Softened: 4–5 min on full power. Sliced, with a knob of butter, to soften quickly before frying.
Times are a guide for typical home portions: ovens, air fryers, microwaves and the size of what you’re cooking all vary. Check meat, poultry and fish with a thermometer before serving. Safe temperatures follow USDA and UK Food Standards Agency guidance, last checked 11 November 2026.