The caramelization process is a simple, yet effective way to pull complex flavors from the simplest of ingredients. When slowly sauteed in butter or oil, sliced onions release their natural sugars and caramelize themselves, yielding rich and sweet, yet savory results. While the process of caramelizing onions takes some time, the resulting flavor adds worthwhile depth to everything from dips to hamburgers.
Cut onions into thin, uniform slices. You want the slices to be approximately the same thickness so that they cook evenly.
Add a generous drizzle of olive oil or a pat or two of butter to a large skillet. Bring the skillet to a medium high heat, until the oil shimmer with heat or the butter has melted and bubbles.
Add the onions to the skillet. Spread the onion slices evenly in the pan and let cook, stirring every few minutes.
Add a generous pinch of salt to the onions after they have been cooking for 10 minutes. If you would like, add a sprinkle of sugar to aid in the caramelization process. Add a little water to the pan if necessary to prevent the onions from drying out. Continue cooking, stirring the onions every few minutes so that they brown, but not burn. If the onions seem like they are about to burn, turn the heat down to medium.
Taste the onions after they have been cooking for around 40 minutes. The onions should be a nice golden brown color. If you like the flavor, you can stop cooking. If you would like to develop an even deeper, more complex flavor, continue cooking for another 10 to 20 minutes.
Pour a few splashes of wine, chicken or beef broth, balsamic vinegar or water into the skillet to deglaze the pan. Scrape up any stuck-on caramelized bits from the bottom of the pan and stir them into the onions. Add another sprinkle of salt, if you would like.
Use the caramelized onions immediately, or cool and store in the refrigerator for up to a week or in the freezer for up to three months.
Use caramelized onions in soups and on top of salads, on sandwiches or burgers, as a pizza topping, to spruce up pasta sauce, and in dips.
Any type of onion can be caramelized, so feel free to use red, white or yellow onions.
Use either Madeira wine or brandy for deglazing; the flavor of both liquors complements the flavor of onions.
Keep an eye on the onions as they cook to prevent burning.