The Most Important Thing to Know
Virtually every recipe that says caramelised onions take 10–15 minutes is lying. Real caramelised onions — deeply golden, sweet and jammy — take 45–60 minutes minimum. Rushing them on high heat gives you browned but bitter onions, not caramelised ones. This is the single biggest mistake people make.
Ingredients
- 3–4 large onions (they shrink dramatically — 4 onions makes about 1 cup caramelised)
- 2 tablespoons butter
- 1 tablespoon olive oil
- Generous pinch of salt
- Optional: splash of balsamic vinegar, white wine or water to deglaze
- 1
Slice onions thinly and evenly
Halve and peel the onions. Slice into thin half-moons — about 3–4mm thick. Uneven slices cook at different rates.
- 2
Heat butter and oil in a wide, heavy pan
A wide pan gives more surface area. A heavy base distributes heat evenly. Medium-low heat. Add butter and oil together — butter adds flavour, oil raises the smoke point.
- 3
Add onions and salt, stir to coat
Add all the onions — the pan will be very full. Add a generous pinch of salt immediately. Salt draws out moisture which speeds up the process slightly.
- 4
Cook on medium-low for 45–60 minutes
Stir every 5–8 minutes. The onions will soften and collapse (10–15 min), turn translucent and pale gold (20–30 min), then slowly deepen to amber and jammy (45–60 min). If the pan gets dry, add a splash of water and scrape up the browned bits — this is flavour.
- 5
Deglaze and finish
When deeply golden, add a splash of balsamic vinegar or white wine. Scrape the bottom of the pan. Cook another 2–3 minutes until the liquid is absorbed. Taste and adjust salt.