Browning Onion Recipe

Peel and slice

Peel the outer skin from the onion. Trim root and stem ends. Cut the onion in half pole-to-pole and slice thinly, about 1/8 to 1/4 inch (3–6 mm) thick. For faster, more even browning, slice uniformly.

Measure out oil, butter, salt, and sugar (if using) and have the deglazing liquid ready near the stove.

Heat the pan

Place a wide skillet (stainless steel or heavy-bottomed) over medium heat. Add the oil and let it warm 30–45 seconds until it shimmers but before it smokes.

Add butter and onions

Add the butter to the warm oil and swirl to melt. Add the sliced onions in a single layer if possible. Stir once to coat with fat.

Initial sweat

Reduce heat to medium-low. Sprinkle the onions with the salt and optional sugar. Cook without vigorous stirring for 4–6 minutes until they begin to soften and edges become translucent. Stir gently every 1–2 minutes to prevent sticking.

Caramelize and brown

Increase heat to medium. Continue cooking, stirring every 1–2 minutes and scraping browned bits from the pan with a spatula. If onions begin to stick or dry out, add 1 tablespoon of the deglazing liquid to loosen browned bits and stir. Continue until onions reach an even golden-brown to deep mahogany color, about 15–25 more minutes depending on thickness and pan. For deeper browning, occasionally let onions sit undisturbed 2–3 minutes to encourage fond formation, then stir.

Finish and season

When onions are richly browned and aromatic, turn off the heat. Taste and adjust seasoning with additional salt and a grind of black pepper if desired. If the pan has stuck dark bits you want incorporated, add the remaining deglazing liquid and stir to lift and coat the onions.

Use browned onions immediately in recipes (soups, sauces, burgers, pizzas) or cool completely and refrigerate in an airtight container for up to 4 days. For longer storage, freeze in portions for up to 3 months.