Slice onions and put them in a pan over medium heat.
Drizzle with vegetable oil, then toss to coat. Cover the onions with a lid and cook for 10 minutes.
Stir the onions, replace the lid and let them continue to caramelize for another 10 minutes.
Stir and continue cooking for another 5 minutes, when golden brown and soft.
Video
Notes
Tips
Oil - Don't use more than 2 tablespoons of oil or butter, or the sautéed onions can become too greasy. Be sure to put a lid on the sauté pan - this speeds up the cooking and helps the onions retain their moisture.
Make them Vegan - To make the onions vegan, use a plant based oil or butter.
Depending on how caramelized you'd like them to be, you can cook your onions on low heat for up to one hour in total.
To Store
Refrigerate - Once the onions are cooked, let them cool to room temperature and place them in an airtight container in the fridge and they will keep up to 7 days. You can then use them as is in recipes, or you can reheat them gently on the stovetop to serve.
Freeze - Store in airtight container or freezer bag up to 3 months. Double wrap to avoid onion odor seeping into other frozen goods.