The Best Way to Caramelize Onions (and Why It Takes So Long)

Real caramelized onions, the deep amber, jammy kind, take much longer than most recipes admit. Understanding why helps you stop rushing a process that simply can't be rushed.

Why It Takes 40 Minutes, Not 10

Caramelization is the slow breakdown of natural sugars in the onion, which only happens properly over low, steady heat. High heat browns the outside before the inside has softened, giving you scorched bits instead of that silky sweetness.

Slice Them Evenly

Uneven pieces cook at different rates, so some will burn while others are still raw. Slice onions into even, thin strips so the whole batch cooks together.

Low Heat, a Lot of Patience

Cook onions in butter or oil over medium-low heat, stirring occasionally, for at least 35 to 45 minutes. They'll go through several stages, translucent, then golden, then a deep amber brown, and rushing any of those stages leads to bitterness.

Add a Splash of Water If They Stick

If the onions start sticking or the pan looks dry before they're fully caramelized, add a small splash of water and scrape up the browned bits from the bottom of the pan. This keeps them from burning while you finish the process.

A Pinch of Salt Speeds Things Up

Salting the onions early helps draw out moisture, which speeds up the softening stage without affecting the final flavor. Just don't add so much that the dish ends up over-salted by the time they've reduced down.

Once they're done, caramelized onions keep well in the fridge for about a week, so it's worth making a bigger batch than you need for just one meal.