Snowy on top, bright underneath, and cracked wide open by the heat.
The first step is the one to not skip. Rubbing the zest into the sugar with your fingertips takes about a minute and it is the whole difference between a cookie that tastes faintly of lemon and one that tastes like lemon. The sugar goes damp and the whole bowl smells like the outside of the fruit. Zest stirred in later never does this.
The crinkles are a matter of coating, not technique. Granulated sugar first, then powdered sugar in a heavier layer than feels reasonable. The dough spreads underneath while the sugar shell stays put, and the cracks are simply the shell giving way.
The dough
The coating
Zest the lemons before juicing them. It is nearly impossible to zest a lemon that has already been cut, and this is the kind of thing you only forget once.
If the coating looks thin after baking, the powdered sugar went on too lightly or the dough was too warm when it was rolled. Both are fixed the same way: chill the scooped balls another ten minutes, then coat them again just before they go in.
“A minute spent rubbing zest into sugar is the only real work in this recipe, and it is where all the flavor comes from.”