2 large onions, sliced
50ml white or red wine, vegetable or chicken stock, balsamic vinegar, or water
Salt and black pepper
- Place a heavy stainless steel or cast iron pan over a medium-low heat. Add the butter and oil. When the butter has melted, stir in the onions.
- Cook for 40-45 minutes, checking and stirring every 5-10 minutes.
- After 40 minutes, the onions should look golden and smell caramelised. If you like the way they taste, stop cooking now. For an even deeper caramelised flavour, continue cooking for another 5-10 minutes, adding a splash of water if they begin to catch or burn on the bottom of the pan.
- When the onions have finished cooking, add the wine, stock, balsamic vinegar or water. As the liquid bubbles, scrape up the sticky bits from the bottom of the pan using a wooden spoon and stir it into the onions. Use additional liquid as necessary. Season the onions to taste.
- If you’re not using the onions immediately, let them cool in the pan, then transfer them to an airtight container and store in the fridge for up to one week.
Common mistakes to look out for:
- Using only butter
Butter adds fantastic flavour, but it’s best to include a splash of oil to avoid burning.
- Crowding the pan
If you pack too many onions into the pan, they’ll take forever to caramelise. For a 30cm pan, caramelise no more than two large onions at a time.
- Too hot
Caramelising onions is a completely different process to frying, and it takes time. Keep your pan over a medium-low heat for the entire process.
- Not deglazing
Take full advantage of the flavoursome brown bits in the bottom of the pan by deglazing with stock, wine, beer, or vinegar – whatever best fits the dish for which your onions are destined!
- Being impatient
Caramelisation takes time – don’t declare them ready too early! The onions should be a rich brown colour, much reduced from where you started, and very soft.