How to Properly Caramelize Onions
Good caramelized onions provide a deep, complex base for soups, tarts, or sandwiches. It takes about an hour of attention to move them from translucent to the deep brown state where the sugar has fully converted.
Patience is your primary ingredient.
Do not crowd the pan; use a wide surface area so the moisture can evaporate evenly. If you pile them too deep, they will steam instead of brown.
- Large stainless steel or cast iron skillet
- Wooden spatula
- Chef's knife
What goes in.
- 3 lbYellow onions, peeled and sliced into uniform quarter-inch strips
- 3 tbspUnsalted butter
- 1 tbspNeutral oil
- 1 tspKosher salt
Capturing the Fond
When a brown crust forms on the bottom of the pan, add a tablespoon of water or broth. Scraping this up incorporates the concentrated flavor back into the onions.
The method.
Heat the fat
Place your skillet over medium heat. Add the butter and oil. Once the butter foams and stops hissing, add the onions.
Initial wilt
Toss the onions to coat them in the fat. Cook for 10 minutes until they soften and turn translucent. Sprinkle with salt to draw out the moisture.
Low and slow
Reduce the heat to medium-low. This is the stage where you leave them alone for 10-minute intervals, stirring only enough to prevent burning.
Brown and scrape
As the onions turn golden, increase the frequency of your stirring. If the bottom of the pan gets dark brown, add a splash of water and scrape the pan clean.
The finish
The process is complete when the onions are uniformly dark amber and have the consistency of marmalade. Remove from heat immediately.
Other turns to take.
Balsamic Finish
Add a teaspoon of balsamic vinegar in the final two minutes to provide a sharp acidic contrast to the sweetness.
Herbed
Toss in a sprig of fresh thyme halfway through the cooking process for an earthy aroma.
When it doesn't go to plan.
Cut the onions with the grain, from root to stem, to ensure they hold their shape during the long cooking time.
If you find yourself with too much liquid in the pan after 30 minutes, increase the heat slightly and remove the lid if you were using one.
Store leftovers in an airtight container for up to five days, or freeze them in ice cube trays for easy portions later.
The ones that keep coming up.
Why are my onions bitter?
You likely burned them. The sugars have carbonized rather than caramelized. If they turn black, start over.
Can I use red onions?
Yes, but they take longer to show their color and can sometimes taste slightly more astringent than yellow onions.