Caramelized onions are a kitchen staple that elevate any dish with their rich, sweet, and deeply savory flavor. Slowly cooked to perfection over an hour, they transform into golden-brown strands of melt-in-your-mouth goodness. Their velvety texture and complex taste add depth to sandwiches, soups, and even simple pasta dishes. The process is surprisingly hands-off, requiring just a bit of patience and a watchful eye. Once you try them, you’ll wonder how you ever cooked without this versatile ingredient.

Perfect for meal prep, these onions keep well and can be used throughout the week to enhance your favorite recipes. The aroma of onions gently sizzling in butter or oil is irresistible, filling your kitchen with warmth and anticipation. Whether you’re a seasoned cook or just starting out, mastering this technique is a game-changer. In just over an hour, you’ll have a jar of golden magic ready to transform everyday meals into something extraordinary.

What You’ll Need?

2 tablespoons extra-virgin olive oil (or substitute with butter for a richer flavor)
4 medium yellow onions, halved and thinly sliced (use a mandoline for even slices)
½ teaspoon sea salt (adjust to taste)

How to Make It

Heat the oil: In a 12-inch cast iron skillet, warm the olive oil over medium heat until shimmering.
Sauté the onions: Add the sliced onions and cook for 5 minutes, stirring occasionally, until they begin to soften.
Add salt and reduce heat: Sprinkle in the sea salt, then lower the heat to medium-low. Cook for 50 to 80 minutes, stirring every few minutes, until the onions are very soft, golden brown, and caramelized. (Timing depends on onion size and stove heat.)
Adjust as needed: If the onions start to stick, reduce the heat to low. For deeper caramelization, increase the heat slightly and stir continuously to prevent burning.
Finish and serve: Once the onions are deeply browned and sweet, remove from heat and use immediately or store for later.

Perfect Pairings: Serving Suggestions

Caramelized onions are a versatile topping that can elevate many dishes. Try them on burgers, sandwiches, or flatbreads for a sweet and savory twist. They also pair beautifully with roasted vegetables, mashed potatoes, or as a garnish for soups and stews.

Store and Savor: Storage and Reheating Tips

Store leftover caramelized onions in an airtight container in the fridge for up to 5 days. To reheat, warm them gently in a skillet over low heat or microwave in 30-second intervals, stirring in between. You can also freeze them in small portions for up to 3 months—perfect for quick meals!

Flavor Twists: Recipe Variations

Experiment with different flavors by adding balsamic vinegar or red wine during the last 10 minutes of cooking for a tangy kick. For a richer taste, stir in a teaspoon of brown sugar or a splash of soy sauce as the onions caramelize.

Time-Saving Hacks

If you’re short on time, slice the onions in a food processor to speed up prep. To reduce cooking time, increase the heat slightly during the last 10 minutes, but stir constantly to avoid burning. Alternatively, make a larger batch and freeze portions for future use.

Essential Equipment Guidance

A 12-inch cast iron skillet is ideal for even heat distribution, but any heavy-bottomed pan will work. Use a wooden spoon or silicone spatula for stirring to prevent scratching the pan. If you don’t have a lid, cover the pan with foil to trap moisture during the initial softening stage.