Bacon Fat Will Utterly Transform Your Caramelized Onions

Sweet, sticky, and gloriously golden brown, caramelized onions are one of those super-versatile ingredients that can be used to elevate all sorts of dishes. Whether heaped onto a juicy burger, scattered across a savory tart, used as the base for a French onion soup, or stirred into creamy pasta to make caramelized onion fettuccine, these slow-cooked onions always add a wonderful depth of flavor.

While they do take a long time to cook, it's very simple to make caramelized onions. All you need are onions, a heavy-bottomed pan, some fat, and a little patience. But if your usual fat of choice is butter or oil, then switching to bacon fat is a must-try trick that transforms your onions, giving them an extra burst of rich and savory flavor. You can render your own bacon fat by cooking bacon slowly, either in the oven or on the stove, then draining, skimming, and storing the fat. The smoky, meaty richness is perfect for frying or sautéing everything from eggs and rice to vegetables such as brussels sprouts. The robust savory flavor of the fat also highly complements the sweetness of caramelized onions. As the onions cook, they become infused with bacon flavor while their natural sugars caramelize.

The key to caramelizing onions is to cook them for a long time over low heat. Butter is a great fat to use in this case, as it can bring its richness without burning, as it's prone to do at high temperatures. Bacon fat brings even more flavor, though, and since the smoke point is similar for both fats (325 degrees Fahrenheit for bacon fat, and around 350 degrees Fahrenheit for butter), it makes for a simple switch.

The easiest way to cook onions in bacon grease is to cook bacon in a pot, remove it, then use the fat left behind to caramelize the onions right away. However, if you render the fat, remove it from the pot, and filter it before storing it in a jar in the refrigerator, you can have a bacon grease stash that lasts way longer, so that you always have a supply ready for cooking.

If you're using solid bacon fat from the fridge, just add a couple of tablespoons to a skillet over a low-to-medium heat, add the onions, and let them cook slowly until golden brown to deep brown in color. The sliced onions will become meltingly tender and deliciously sweet, and also infused with an appetizing smoky flavor from the bacon fat. The final product will be pure magic in sandwiches, burgers, or even in breakfast dishes to take advantage of the bacon flavor.

If you want to take your bacon-infused caramelized onions to even greater heights, then try adding some whiskey, such as bourbon, to the mix. Just slowly cook the sliced onions in the bacon fat, and when the pan starts to look a little dry, add a teaspoon of whiskey. Try to fit in two to three teaspoons of booze before the onions are finished and enjoy the rich sweetness of the whiskey that also brings out the onions' aroma.

You can also try adding a few tablespoons each of balsamic vinegar and soft brown sugar to the onions during the final five minutes of cooking time. The result is a sweet-yet-sharp flavor that makes the caramelized onions more like a tangy chutney or relish. If you want to go beyond simply seasoning the onions with the usual salt and pepper, try adding some fragrant fresh herbs, such as chopped rosemary and thyme, to the pot towards the end of cooking. Or go for curry powder, chili flakes, or other ground spices if you really want to ramp up the flavor.