Always zest your lemons before cutting and juicing them—whole lemons are much easier to zest than halved ones, and you'll capture maximum aromatic oils for superior lemon flavor.

Bring eggs and butter to room temperature before mixing to ensure smooth emulsification and a fluffy, tender crumb structure rather than a dense brownie.

Test for doneness when a toothpick inserted in the center has a few moist crumbs—lemon brownies continue cooking as they cool, so remove them slightly underbaked for maximum fluffiness.

Add a pinch of lemon zest directly into your powdered sugar glaze and reserve fresh zest as a garnish to create layered citrus complexity that intensifies the bright flavor profile.

Whip egg whites to soft peaks separately and fold them in last for extra airiness and a lighter, more cake-like texture that distinguishes these brownies from their chocolate counterparts.