Caramelized onions add a savory sweetness to many dishes from Lyonnaise potatoes, French onion soup and steaks to a sandwich topping They are easy to make once you know how. Many beginners tend to cook the onions over to high a heat, burning them rather than caramelizing. I use olive oil and a tablespoon of butter but you can use just oil or clarified butter. I would stay away from just butter though as the solids in the butter will burn. Cooking time will vary depending on the amount of onions used. It may takes as little as ten minutes to as long as 30 minutes or more. Start cooking on medium heat then turn the heat down to medium low after about 10 minutes to prevent burning. You will find that many times you will need to reduce the heat while cooking with cast iron due to its excellent heat retention. Add 1 tsp sugar at the beginning and another about halfway through the cooking time. The sugar is optional as the natural sugars in the onions will caramelize but it speeds up the process a bit and adds a nice touch. Many recipes call for an onion per person. At first thought you might think, “Gawd, that way too much onion!”, but after you see how much they reduce you will understand.
Here are four jumbo Vidalia onions sliced and ready for the skillet.
I used about three tablespoons of olive oil and a tablespoon of butter heated before I add the onions. Now stir to coat the onions with the oil. Continue stirring occasionally, scraping the onions from the bottom of the skillet.
Here’s what they look like at about twenty minutes. At this point I might use them for fajitas or yellow squash and potatoes.
Here we are at about 30 minutes with nicely caramelized onions. I tend to make more than the recipe calls for as I can refrigerate them for a few days or freeze them for up to a month.