Ingredients2-4 yellow onions
2 tablespoons butter, extra-virgin olive oil, or a mix
2 tablespoons white or red wine, vegetable or chicken stock, balsamic vinegar, or water
Stuff you will needStainless steel or cast-iron skillet
DirectionsSlice the onions: Trim the tip and root from the onions, cut them in half and remove the skins. Slice the onion from root to stem into thin slices. (Alternatively, you can dice the onions.)
Melt the butter: Place your skillet over medium heat and melt the butter.
Add the onions: Add all the onions to the pan and stir them gently to coat with butter.
Caramelize the onions: Check the onions every 5 to 10 minutes. Stir the onions and scrape up any fond that forms on the bottom of the skillet. Exact cooking times will vary with the number of onions you're cooking, their liquid and sugar content, and their age:
Around 10 Minutes: Onions will start to soften and turn translucent in spots. They will release a lot of liquid into the pan. • Around 20 Minutes:Onions will be very soft and starting to break down. Some onions will start to show spots of caramelization and you may see some fond starting to build up in the pan. They will also start to smell caramelized. Adjust the heat if the onions seem to be cooking too quickly or you notice any burnt spots. • Around 30 Minutes: Onions should be light blonde in color and starting to become jammy. More fond is starting to build up, but it should still be fairly easy to scrape it up with the evaporating liquid from the onions. • Around 40 Minutes: Onions are golden and starting to smell very caramelized. Taste one — if you like the way they taste, you can stop now! For even deeper caramelized flavor, continue cooking. • Around 50 Minutes and Beyond: Continued cooking will result in darker, richer, even more caramelized onions. Continue checking the onions every 5 to 10 minutes until they reach your desired level of caramelization. The fond may start to build up on the bottom of the pan — let it be unless it looks like it's starting to burn (in which case, deglaze the pan with a little water).
Deglaze the pan and salt the onions: When your onions have finished cooking, pour 1/4 cup wine, broth, balsamic vinegar, or water. As the liquid bubbles, scrape up the fond and stir it into the onions. Use additional liquid as necessary to scrape up all the fond. Salt the onions to taste.
Cool and store the onions: If you're not using the onions immediately, let them cool in the pan, then transfer them to a storage container. Caramelized onions can be kept refrigerated for around a week or frozen for up to three months.