[extortionist]

America's Test Kitchen actually does suggest adding water to reduce the amount of time needed for caramelization--and not an equivalent amount of water, but much more than the amount of oil you'd use.

The idea is that adding water, raising it to a boil, and covering the pan reduces the amount of time needed to raise the temperature of the onions to the caramelization point, more than offsetting the amount of time needed to remove the water itself. That plus adding some baking soda near the end reduces the overall time considerably.

https://www.youtube.com/watch?v=Ovqhzil3wJw

[sublinear]

I'd rather not comment about the reliability of ATK because that would be missing the point, but their recipe seems overly fussy and anyway they cut their onions too long in that video. I think it's kind of gross when you have dangling onion strands.

Slow cook them first for a few hours at a low temperature and then caramelize after. All your onion in a dry pot. Don't add water. Strain them when done and you have... soggy pale onions. Heat up the biggest pan you have and add some butter to do the caramelization (don't crowd the pan like they do in their video). Add some good balsamic vinegar and brown sugar while you're at it. Be sure to make a huge batch so you can freeze some for later. Don't bag and freeze before letting the onions come to room temperature. It's a lot of water in them onions man, but you can use that strained out water for a vegetable stock!

[thomasfromcdnjs]

I've got my own invented version of this style. I will boil them in a cm of water or something at the perfect time it evaporates I then add the oil.

I don't like them like the Americans do but there is lots of to play with it. (I've even started boiling onions whole before I use them in a bunch of other dishes)

Highly recommend it.