When: June 27
National Onion Day on June 27th celebrates the indispensable allium that forms the aromatic base of virtually every cuisine on earth. The onion's chemical complexity — responsible both for making you cry and for producing the rich, sweet caramelized depth that defines slow-cooked dishes — makes it one of the most scientifically interesting vegetables in the kitchen.
Onions make you cry because they evolved a chemical defense mechanism against being eaten — when cut, they release enzymes that react with sulfur compounds to produce syn-propanethial-S-oxide, which vaporizes and irritates the eyes.
Workers who built the pyramids at Giza were paid, in part, in onions. This is not legend — it's documented in ancient Egyptian records inscribed on the pyramid walls themselves, which note expenditures of silver for radishes, garlic, and onions consumed by the labor force. The onion was not a side note to ancient Egyptian life; it was currency, food, and religious symbol simultaneously. Onion-shaped objects were placed in the eye sockets of mummies to represent the roundness of eternal life. The concentric rings of the cut onion signified endless cycles. The entire ancient world took the onion considerably more seriously than we do. The cultivated onion (Allium cepa) has been grown for at least 5,000 years, appearing in Sumerian texts, ancient Chinese records, and Sanskrit writing. It may have originated in Central Asia, though the earliest cultivated specimens appear in Iran and West Pakistan. Unlike many ancient crops, the onion left no wild ancestor that's been definitively...