Caramelized onions are an easy and inexpensive way to add amazing flavor to the simplest dishes.
To make the caramelized onions, trim the ends off the onions, cut them in half vertically and peel. Remove the core and thinly slice the onion vertically (from the core to the opposite end).
Preheat a large, heavy-bottomed pan over high heat. Add the oil and onions. Cover the onions to help bring out some of their moisture. After about five minutes, uncover, add the salt, and stir. Leave uncovered and reduce the heat to medium low. Continue to stir from time to time, so they brown evenly. This will take between 45 minutes to an hour.
If the onions start to brown unevenly, you can add a little bit of water. This will help to even out the color. As they start to caramelize, you will need to stir more frequently. When done, they will sort of melt into each other and be a rich brown color.
For every 4 cups of sliced onions, use 1 tablespoon of oil and 1/2 teaspoon of Kosher salt.
To remove all of the stuck on bits in your pan, simply add water to the pan and bring it to a boil to release.
Here are two great supporting recipes:
Alsatian Onion Tart
Tapas-Style Pork Tenderloin