A Splash Of Whiskey Gives Caramelized Onions The Best Flavor

Caramelized onions are a versatile little ingredient. They're sweet enough to go in almost anything, be it a side dish or main course. You can make caramelized onions in your slow cooker or quickly steam your onions to top a burger, and they'll come out rich and sweet from the process. But you can add even more complexity to the recipe with the flavor of whiskey. 

They pair well partly because of what happens during the caramelizing process. You're using heat to break down natural sugars in the onion, causing a chemical reaction that browns them and gives them a sweet, nutty taste. Once you cook away some of the alcoholic burn of whiskey, it's got a fairly similar flavor profile, allowing it to enrich the cooked onions' taste.

All told, you can add up to a quarter cup of whiskey, but add it slowly and carefully. Alcohol can flare up, so it's best to lower the heat or remove the pan from the burner altogether.  To avoid overpowering the natural sweetness of the onions, add only a couple of tablespoons at a time and allow the onions to absorb the flavor first. Keep in mind that adding whiskey at the beginning of cooking allows more alcohol to burn off and leaves you with smokier notes. Adding whiskey in the final few minutes gives the caramelized onions a stronger bite.

You'll find recipes out there with any variety of whiskey, bourbon, or even brandy, but you typically want sweeter varieties. In general, American bourbons tend to be sweeter than regular whiskey, but they aren't the only options. For example, a honey whiskey is sweeter than your average spirit while retaining the oak-accented flavor from its barrel-aging process. That said, you can also add whiskey and honey separately to similar effect.

Other sweet variations include whiskeys made with an especially high amount of corn or whiskeys aged in certain types of casks, such as sherry or even former rum casks. You can even find salted caramel whiskey to help you build on those caramelized flavors. Keep in mind that different whiskeys add different notes, so check the bottle or rely on brands you like. If you get it right, you'll have some strong flavors in the background to deepen the caramelized onion flavor