Monday, November 14, 2011

All Hail Cast Iron

A friend asked me about cast iron and my seemingly unnatural love of it recently. Specifically, she asked me about "curing" or "seasoning" it, a question most common among folks who have cast iron but don't use it too much. Simply put, curing or seasoning cast iron simply refers to the application of a small amount of fat to the pot or pan, then heating it for awhile to set the fat into the pan. Scientifically speaking (and thus quoting Harold McGee in On Food and Cooking): "The oil penetrates into the pores and fissures of the metal, sealing it from the attack of air and water." Furthermore, the fatty acid chains oxidize and bond to form to form a hard, protective layer on the surface of the pan, "just as linseed and other 'drying oils' do on wood and paintings". To put it simply: the fat bakes into the pan, sets, and protects it from rusting, while creating a surface that, when heated thoroughly, is essentially non-stick.

Of course, one wants to preserve this seasoning. To begin with, many cast iron pans sold these days are "pre-seasoned" and are all set to go. However, if you are surfing the thrift store and yard sale circuit, and find a great pan for a couple bucks that is all rusty and beat up (or if you have this very pan hidden away in the depths of your lower cupboards), never fear, for it can be salvaged by scrubbing all of the rust away with an abrasive metal scrubbie, drying it completely, then rubbing it with some fat. Canola oil is fine. Pop it in to a 350° oven for an hour or so. It'll smell weird, but don't worry. Then, turn off the heat and leave the pan in the oven overnight. Good as new. As far as maintenance: DO NOT USE SOAP on the pan. This will remove the protective fatty later described above (which can be replaced using this same process when, unavoidably, someone comes over and "helps" with the dishes, but really--you don't want to do this every time). Instead, scrub it out the same way you normally would, just don't use soap. If anything gives you a hard time coming out (a result of food sticking due to not giving the dense cast iron plenty of time to heat up before cooking--i.e. 5 solid minutes over at least a medium flame), pour in some kosher salt for added abrasiveness. Just don't lose that fat layer. Dry it thoroughly and store (I actually keep mine in the oven sometimes, as the pilot light provides enough heat to ensure it is always dry). You shouldn't need to re-season it; in fact, the fat used each time you cook will build on the coating already present, creating a slick layer of seasoning that should last forever. This is one reason things cooked in cast iron always taste so great: the subtle flavors of a thousand meals past.
And how about a quick, easy, one-pan route to killer tri-tip (or any steak for that matter) with romesco sauce inspired by Mr. Mark Bittman:
  • Get a cast iron pan smoking hot. Get an oven to 450°.
  • Season a hunk of meat. Add a touch of canola oil to said pan. Add meat. Throw some whole almonds and grape tomatoes in the pan next to the meat.
  • Get a lovely sear on the first side of the meat. Nice, dark golden brown. 3-4 minutes. Flip meat and remove almonds and tomatoes. Replace them in the pan with some chopped shallots and move the pan to the oven.
  • In a food processor, mince 2 cloves of garlic. Add almonds and tomatoes. Puree while drizzling in some olive oil until it tastes good. Season with salt and pepper and perhaps some red wine vinegar.
  • Remove steak from oven when it is done to your liking. Let it rest. Slice and serve with the sauce and what are now carmelized shallots. (Admittedly, the pictures prove that my appetite is matched by only my impatience as a long rest prevents some of the juice from escaping. But hey. Do as I say and not as I do, kids.)

Moral of the story here: use that cast iron! It's cheaper and better than pretty much all other cookware out there. And don't forget to remember meals past while cooking new ones in this beauty.