When we increase the heat and cook most of the water out of the onions, they will brown. We call this caramelizing. The heat causes the proteins to release amino acids, which react with the sugars to create a flavor at once sweet, savory, and nutty. This is one of the most extraordinary reactions in the kitchen, so much so that a well-known dish features caramelizing: French onion soup.
To slice onions, first knock out the core.
If you don’t remove the core, your onions will remain attached at the root end. Leave the root when dicing an onion.
Cut from the outside, angling toward the center.
Your onions should be sliced into a similar size and shape so they caramelize evenly.
Onions caramelize nicely in an enameled, cast-iron pot.
Onions are 95 percent water and will release liquid as they cook.