The macaron shell may look dainty and improvised, yet its geometry follows a tight rule: about 3.5 centimeters in diameter. Shift this “standard height” even a few millimeters and the whole dessert begins to lose its internal equilibrium of air, sugar and fat.At that size, the macaron behaves like a small engineered system. The thin meringue dome, built on controlled protein denaturation in egg wh...More