Civilizations have fought over it, sacrificed for it, slaved over it. Perhaps chocolate’s biggest mystery is its endurance as the world’s most-loved food. Few foods in the world have been so coveted and innovated–as payment for taxes, a token of affection, or a reward for accomplishment. Today, gastronomic chocolate takes all forms: sweet, salted, spiced, as toppings, in dishes and drinks. It’s the must-have in mole, the zing in zucchini bread, and turns an after-dinner drink from a nightcap into the sublime.