At some point in their life, every able-bodied human will be called upon to caramelize onions. If you are Indian, this might happen three times in one evening. So let us learn to do this right.
Let’s say you start with one yellow onion. Peel it and chop it. You do not want chunky pieces of onion. What you want is to maximize the cut surface area to expose more of it to the saute it is about to undergo. You can do this one of three ways: slice the onion paper thin; or first give it cross cuts with a sharp knife to produce a fine dice; or, get lazy and puree in a food processor with a few tablespoons of water. All methods work, but the wet purees will take a few minutes to lose their water, and only then will the onion start to caramelize. With the food processor, make sure to pull out a few chunks the blades inevitably leave behind and chop them by hand.
Choose a thick-bottomed pan that will not allow the onions to burn. Stainless steel is best; Calphalon will work; you do not need Teflon. About three-four tablespoons of oil per medium onion is the proportion of oil you need. The flame should be medium-high at first. Be careful not to overfill the pot! If the uncooked onions come up halfway up the pot sides, they will steam instead of searing. Also, no lid needed.
Now, if you caramelize the Indian way, you will saute on medium-high for fifteen minutes or so, every few minutes giving the onions a vigorous stir. If you caramelize the Western way, you will turn the heat down to low after they first start sizzling, and keep the oil at a simmer for a good 45 minutes to an hour, only stirring every ten minutes or so. I think the Western way draws more sweetness out of the onions and is great when onions are the star of the show. In contrast, in Indian dishes, caramelized onions usually are the base for a spicy gravy.
Sprinkle of salt:
After they have started sizzling, I usually add a sprinkle of salt. This draws moisture out of the onions and helps them caramelize faster.
As the onions cook, they will first get translucent, then the edges will start to brown. And their volume will shrink. There may be brown bits stuck to the pan as well; don’t worry about them! As long as you used a thick-bottomed pan that distributes heat well, this is fine. Remember, dark brown = good, black = bad. No doubt it is a subtle difference. But if you notice the edges turning black instead of brown, turn the heat down a bit. As it proceeds, it is wise to turn the heat down a bit anyway.
You can stop when you see some brown, or wait till you see mostly brown. It is a judgment call. The middles of the onion pieces will still be translucent till the end. If you want to scrape up the brown bits stuck to the pan, you can either wait till the next liquid comes in — whether it is tomatoes, yogurt, or other meat or vegetables — as they steam, the brown bits can be easily deglazed. If no further liquid is coming in, cover the pan for a few minutes, allow the onions to sweat, and the resulting liquid can be used to scrape them up.
The caramelization process:
After having done this a few hundred times, one might wonder — what on earth is going on? Well essentially the sugars in the onion oxidize and break down, browning occurs, and produce that familiar aroma. It is the same kind of caramelization process that is used while making creme caramel, otherwise known as flan; and a multitude of other desserts. Here is more information about it.
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