The Food Lab: Better Home Cooking Through Science

of the same family as tomatoes (though completely different
from unripe green tomatoes), it’s actually most closely
related to gooseberries. The flavors of the two—dominated
by a citrus-like tartness with a distinct, savory finish—are
remarkably similar as well, though gooseberries tend to be
sweeter. One of the great things about tomatillos is that they
are also quite high in pectin, the sugar-based jelling agent
that is the primary thickener in most jellies. If you include
tomatillos, you don’t really need any other thickener in your
chili (many classic tomatillo-less recipes call for flour or
another starch), and the tartness it brings to the party is a
welcome flavor addition as well. I char mine under the
broiler to maximize that smoky aroma.
It’s in recipes like these when the importance of every
detail really comes out: Charring every surface of the chiles
to maximize smokiness. Carefully monitoring your roasting
tomatillos so that they char and soften while still retaining
some of their fresh acidity. Sometimes the process of slowly,
deliberately building flavors is just as rewarding as the
finished dish.