Cooks tend to cut vegetables into nice, even shapes. But recently my friend Mikel Zeberio reintroduced me to a technique that my mother taught me years ago. When preparing potatoes for the Basque stews Marmitako and Porrusalda, he cuts the tubers into irregular chunks called cascadas; the word derives from the Spanish verb cascar, meaning to crack. Holding a potato in one hand, he inserts a knife partway into its flesh and twists it to break off briskly one jagged piece after another. According to Mikel, the cascadas' roughly hewn surface releases more starch—which thickens soups and stews—than an evenly cut slice would. It's easy to master; you could even say it's a snap.