For years we’ve seasoned cast-iron skillets and other cast-iron cookware in the test kitchen by placing it over medium heat and wiping out the pan with coats of vegetable oil until its surface turns dark and shiny. When a pan starts to look patchy, we simply repeat the process. But when we heard about a new method for seasoning cast iron that creates a slick surface so indestructible that touch-ups are almost never necessary, we were intrigued. Developed by blogger Sheryl Canter, the approach calls for treating the pan with multiple coats of flaxseed oil between hour-long stints in the oven.

How We Tested This Method

We carried out Canter’s approach on new, unseasoned cast-iron skillets and compared them with pans treated with vegetable oil—and the results amazed us. The flaxseed oil so effectively bonded to the skillets, forming a sheer, stick-resistant veneer, that even a run through our commercial dishwasher with a squirt of degreaser left them totally unscathed. But the vegetable oil-treated skillets showed rusty spots and patchiness when they emerged from the dishwasher, requiring reseasoning before use.

Why did the new treatment work so well? Flaxseed oil is the food-grade equivalent of linseed oil, used by artists to give their paintings a hard, polished finish, and it boasts six times the amount of omega-3 fatty acids as vegetable oil. Over prolonged exposure to high heat, these fatty acids combine to form a strong, solid matrix that polymerizes to the pan’s surface.

How to Season Cast Iron with This Method

Although lengthy, seasoning with flaxseed oil is a mainly hands-off undertaking. We highly recommend the treatment: