The Food Lab: Better Home Cooking Through Science

golden brown stage. Additionally, the sugars and proteins
that get stuck to the bottom of the pot as the onions cook
rapidly turn dark brown, because of their direct contact.
So, the question is, if you’re cooking with high heat, what
can you do to simultaneously even out the cooking all
across the onions, remove the sticky browned gunk from the
bottom of the pan, and regulate the overall temperature so
that nothing burns? If you’ve ever made a pan sauce, the
answer is so blindingly simple that I’m surprised it’s not a
completely common practice: just add water.
At first, adding water may seem counterproductive—it
cools down the onions and the pot, forcing you to expend
valuable energy heating it up and evaporating it. But here’s
the deal: both the browned patina on the bottom of the pot
and the browned bits on the edges of the onions are made
up of water-soluble sugar-based compounds that happen to
be concentrated in a single area. Adding just a small amount
of liquid to the pot at regular intervals means these
compounds get dissolved and redistributed evenly
throughout the onions and the pot. Even distribution leads to
even cooking, which leads to no single part burning before
the rest is cooked.
So what does all this mean for your onions? It means
that you can cook them over a much higher flame (medium-
high works well—even maximum heat is feasible, though it
requires a little more attention), and every time they threaten
to start burning, just add a couple tablespoons of water and
you’re smooth-sailing once again.
As I said, the flavor is not quite as deep and sweet as
traditionally slow-cooked onions (sometimes there are