cook · side · american

How to Caramelize Onions

Caramelized onions are patience rewarded. What starts as a pile of sharp, white slices becomes something completely different — sweet, jammy, and deeply flavored.

Before you start

This is a hands-off process that cannot be rushed

The onions will spend most of their time cooking unattended, but they need occasional stirring to prevent sticking. Plan to be nearby for the full cooking time.

Ingredients

The patience principle

Low heat is the only way

Medium-low heat lets the onions release their moisture slowly while their natural sugars caramelize. Higher heat will brown the outside before the inside softens, giving you burnt edges and raw centers.

Step by step

  1. Slice the onions. Cut onions in half through the root, then slice into thin half-moons about 1/8-inch thick. Keep slices even so they cook at the same rate.
  2. Start cooking. Heat butter in your pan over medium-low heat. Add all the onions and salt. They'll pile high at first — that's normal.
  3. Let them wilt. Cook without stirring for 5 minutes. The onions will start to soften and release water, reducing in volume by about half.
  4. Stir and continue. Stir every 8-10 minutes. After 20 minutes, they'll be soft and translucent. After 30 minutes, they'll start turning golden.
  5. Watch for the transformation. Between 35-45 minutes, the onions will deepen to amber, then mahogany. They're done when they're jammy and deeply colored throughout.
  6. Deglaze if needed. If brown bits stick to the pan, add 2 tablespoons water and scrape them up. This fond adds flavor to your final onions.

Tips & troubleshooting

Variations

Questions

Can I speed this up with higher heat?
No. High heat will burn the outside before the sugars properly caramelize. The slow breakdown of cell walls and concentration of sugars requires time and gentle heat.
Why are my onions still sharp after 30 minutes?
They need more time. Raw onion sharpness doesn't disappear until the sugars fully caramelize, which happens in the final 10-15 minutes of cooking.
What if they start to burn?
Lower the heat immediately and add 2-3 tablespoons of water. Scrape up any stuck bits and continue cooking more gently.

Further reading