Patience is the name of the game when caramelizing onions. The process is slow... but the results are fantastic. As the sliced onions cook, their natural sugars are released. Those caramelize to a beautiful golden brown. These sweet onions can be used in dips, on burgers, in a quesadilla, scrambled with eggs, and more. If there are leftovers, they'll keep in the fridge (stored in an air-tight container) for three to four days. They freeze well too. Just place in a freezer bag and they'll stay for a few months (if they get freezer burn, though, they'll have to be tossed).