Video: Seasoning cast iron with flaxseed oil isn't super new -- Sheryl Canter first wrote about it on her blog seven years ago -- but it has some serious fans. Both Cook's Illustrated and The Kitchn are believers, with the former saying it created "a sheer, stick-resistant veneer, that even a run through our commercial dishwasher with a squirt of degreaser left them totally unscathed".