"Inspired by a Bon Appétit article from a few summers ago, I set my cast iron skillet on my grill as it preheated, and when it was smoking hot, I added a little oil, then lowered in a thin fillet of haddock. The result? Perfectly seared, unmangled fish in just about 3 minutes. I will be using this technique to grill fish all summer. I've been grilling tortillas directly on the grates after the fish finishes cooking, then breaking the fish into pieces and serving it taco-style with slaw, cilantro-lime crema, and lots of fresh lime juice. The slaw and crema can be made a day in advance. Here's the slaw recipe I've been making. On the fish, I like to use cayenne for both color and heat, but if you are sensitive to heat, you can use other dried spices such as paprika, cumin, or dried ancho chile...."