How to Cut an Onion

In this month’s column, the cookbook author Kenji López-Alt answers a question of his own: What’s the mathematically best way to cut an onion?I didn’t go to culinary school. My first real instructor was a book, specifically Jacques Pepin’s “La Technique.” In what feels like a precursor to today’s internet videos, it demonstrates every essential French technique with thousands of hands-only photographs. The onion-cutting method I learned from it is the same one taught at top Western culinary schools, and it’s the method used by most of the cooks at every restaurant I’ve…