People taste our cookies and say the chocolate is really good. The chocolate is good. It is not that good. What they're tasting is salt.
Two different salts, two different jobs
The salt in the dough is a seasoning. It's fine-grained, it dissolves completely, and its job is to keep the sweetness from going flat. A cookie with no salt in the dough tastes dull and one-note — you'll notice something is missing without being able to name it.
The salt on top is a texture and a contrast. It's flaky — Maldon, or any pyramid-crystal finishing salt — and the whole point is that it doesn't dissolve. You get a crystal that crunches and delivers a spike of salinity against the sweet, and the contrast makes the chocolate read as deeper and more bitter than it is.
Timing is the whole trick
Sprinkle it the second the tray comes out, while the tops are still glossy and tacky. The residual heat softens the bottom face of each flake just enough to weld it in place, and the crystal stays intact on top.
Sprinkle before baking and the salt dissolves into the dough — you've just made the cookie slightly saltier and thrown away the crunch. Sprinkle after the cookies cool and the flakes slide straight off onto the counter.
What not to use
- Table salt. Fine, dense, and iodized. It dissolves instantly and tastes sharp. It has a place — in the dough — and it isn't on top.
- Kosher salt. Better, but the crystals are hard little cubes. They read as gritty rather than flaky.
- Too much of anything. A three-finger pinch, scattered from about a foot up so it spreads. You want four or five crystals per cookie, not a crust.
Try it side by side
Salt half a tray and leave the other half plain. Taste one of each, plain first. Most people can't articulate what the salted one is doing differently — they just reach for the second one.