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How Slow Cooking Turns Ordinary Onions Extraordinary
Caramelized onions are a simple kitchen staple that can completely transform a dish. Slow-cooking gives them a rich, savory sweetness that makes them perfect for layering flavor onto everything from grilled steak and burgers to pasta, soups, and sandwiches.
The ingredient list is quite short, just onions, a little butter, some oil, salt, and an an optional pinch of sugar. It’s the process that builds the flavor – and that process is all about patience. Cooking low and slow lets the natural sugars in the onions break down, turn golden brown, and create a jam-like texture and rich flavor that can only be achieved by time in the pan.
Ingredient Notes and Substitutions
Here’s what you need to know about the key ingredients in this recipe. The complete list, including quantities, is in the printable recipe card below.
YELLOW ONIONS: Yellow onions are our first choice for caramelizing because their natural sugar content and balanced flavor develop into a deep, savory sweetness as they cook. Sweet onions are fine too, but they’re a tad pricey to cook down to this degree. Both red and white onions have a more pungent flavor that could overwhelm other ingredients rather than complement them.
BUTTER & OLIVE OIL: A combination of butter and light olive oil provides the best of both worlds. The butter adds rich flavor, while the oil helps prevent burning. Stick with this fifty-fifty ratio for consistent results.
PINCH OF SUGAR: Adding just a pinch of sugar helps jump-start caramelization and enhances the onions’ natural sweetness. Skip it if you’re using sweet onions.
Prep Overview
How to Make Caramelized Onions
Planning to make this recipe? Here’s a quick overview of how it’s done. Detailed, step-by-step instructions are in the printable recipe card below.
Start by heating the butter and olive oil in a wide skillet. Add the onions and coat evenly. Cover and cook slowly, stirring from time to time, until they soften and begin to release their natural sugars. Keep the heat low for best results.
As the onions cook, they’ll gradually change color from pale gold to a deeper amber. Stir often to loosen the browned bits from the bottom of the pan and keep the color even. If they start to stick, deglaze with a splash of water, broth, or wine and continue cooking until they reach the right texture for your recipe.
When finished, the onions will have reduced dramatically in volume and turn a rich golden brown. The exact texture depends on how long you cook them.
In the pan on the left, the onions are beautifully caramelized, but still have some texture, making them perfect for topping a grilled steak or tossing with pasta. In the pan on the right, they’ve broken down to a soft, spreadable consistency that’s ideal for French onion soup or spreading on sandwiches and burgers.
Tips for Success
- BE PATIENT: True caramelization takes time. Rushing with higher heat will brown the onions unevenly and turn them bitter.
- USE THE RIGHT PAN: A wide, heavy skillet (stainless steel or cast iron) allows for even browning and enough surface area for moisture to evaporate. Avoid nonstick.
- DEGLAZE WHEN NEEDED: If the onions start to stick, add just a tablespoon or two of liquid at a time to loosen the flavor-filled bits on the bottom of the pan.
Cooking with Caramelized Onions
If you love the sweet and savory flavor of caramelized onions, you’ll find plenty of ways to use them in our recipes. Try them folded into Blue Cheese Pasta with Bacon, layered on Pork Tenderloin Sliders, or tossed with pasta and crumbled sausage. And, for a classic dish that’s all about rich onion flavor, whip up a batch Easy French Onion Soup.
Caramelized Onions (How-To Recipe)
Ingredients
- 2 pounds yellow onions, halved and thinly sliced
- 1 tablespoon olive oil
- 1 tablespoon butter
- 1/2 teaspoon salt
- Pinch sugar
- Water, or other liquid (see notes)
Instructions
- Melt the butter and olive oil together in a large skillet over medium-low heat. Add the onions, stir to coat, cover, and cook for 12 to 15 minutes, stirring occasionally, until soft and translucent.
- Uncover the pan, raise the heat to medium, and stir in the salt and a pinch of sugar. Continue cooking, uncovered, stirring often and scraping up any browned bits as they form on the bottom of the pan.
- If the onions start to stick or brown too quickly, add water (or other liquid – see notes), 1 tablespoon at a time to loosen them from the bottom of the pan and keep them from burning. Continue cooking until the volume of the onions is considerably reduced and they've turned a deep golden brown.
- If you want the onions to retain a bit of texture (for burgers, steaks, and pasta), stop when they're soft and partially broken down (total time 35 to 40 minutes). For a spreadable, jam-like consistency (for sandwiches, soups, or sauces), continue cooking up to 10 minutes longer.
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Great site.look forward to reading more tips.
Hello; I like caramelized onions a lot; one of our favorite lunch dishes is onion tart with caramelized onions; however, I have one remark – we never cover onions, we just fry them (to get rid off of the liquid) on a minimum flame.