So we are putting our foot down to say, accept no substitutes, Pinterest hacks, or quickly sugared imitations. Put on your patience hat and follow these steps for the perfect caramelized onions.
Slice 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 slices. Keep in mind, thinly sliced onions will burn faster and stick to the bottom of your pan. Aim to slice your onions 1/8″ thick this will prevent them from drying out or burning.
Melt the butter and oil: Place your skillet over medium heat and melt the butter with the oil. You definitely want the flavor of butter in your onions, but butter has the tendency to burn. For insurance, a combination of butter and oil will give you a higher smoking point.
Add the onions: If you pack too many onions into your pan, they’ll steam and produce water. Eventually, they will caramelize, but it will take much longer to get them there. In a 12″ pan, you’ll ideally be able to cook 2 large onions without encountering any steaming problems. Add your onions 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).
What you now have in your skillet is ready to be enjoyed! So go ahead, add a small spoonful of those onions to a slice of baguette with a bit of goat cheese for a quick snack. Stir them into pasta or braised dishes for a richer flavor. Make that French Onion soup you have always meant to. Layer them on top of pizza, a burger, or a salad. I think the point is there probably isn’t a bad dish to add them to. So go, enjoy the fruits of your labor.