The Absolute Best Way To Reheat Caramelized Onions For First-Bite Flavor

Caramelized onions make everything better: burgers, grilled cheese, even pizza. With their delicious sweetness and soft texture, they can make any ordinary dish feel more refined. But even the most foolproof recipe for caramelized onions calls for an ingredient we're often short on: time. Sometimes you simply have to bend the rules a little bit and save time by cooking a large batch of caramelized onions in advance. They can indeed be tricky to reheat in a way that yields the same texture and flavor as when they're made fresh, but it's not impossible. The best way to reheat caramelized onions is on a stovetop, over low heat.

Because the onions are caramelized in a generous amount of fat, you generally don't need to add any more when reheating them. The fat that had solidified around the onions as they cooled down will melt again when you reheat them. You could still use a small amount of butter or oil in the pan if you feel that it's necessary, but make sure it's heated up before you add the onions. To ensure your onions don't burn as you're reheating them, use a non-stick pan in combination with the low heat. The whole process should take about five minutes — don't rush, and stir the onions occasionally so they heat up evenly.

The low heat rule goes for reheating caramelized onions in the oven, too. They burn very easily, so the oven temperature should only be set to 300 degrees Fahrenheit, and you should cover the baking dish with tin foil. This method will take slightly longer than reheating on the stovetop, as the onions can take up to 20 minutes to reheat, but that's still significantly faster than making them from scratch.

You could also make use of your trusty microwave. Reheating caramelized onions in the microwave is perhaps the fastest approach, but it's also the riskiest. If you're not careful, the result can be a mushy and unevenly heated dish. Microwave the onions in 30-second increments, gently stirring after each increment to ensure the even distribution of heat. You have to keep an eye on them to make sure they don't overheat, so it's helpful to do a quick taste test after each stir.

Last but not least, caramelized onions are the least complicated to reheat when you're simply using them within another dish, like caramelized onion mac and cheese or a hearty French onion soup. Just add your refrigerated or thawed onions to the dish, and they will reheat through the cooking process.