I was excited to read your post. I equate the cast iron with the flame broiler as well cause it will caremelize and char like a champ. In fact I couldn't complain if I never had a grill cause the little cast iron pan I have is so awsome.
Just today, I made some excellent carne asada tacos. Check it out :)
Marinade carne asada in onion scraps, soy sauce and assorted seasonings min. 10 minutes
Heat Skillet to med high and toast one side of small tortillas.
Toss carrots cut battonnet style in oil and seasonings and toss on the pan with the meat.
The carrots will be done with the meat & depending it's thickness the meat, it should cook to medium rare VERY fast ( I suggest to flip 3 times in 90 second intervuls if it's 2 cm. thick).
For salsa fresca, small dice some tomatoes and onions, add some corn and squeeze some lemon or lime & season.
Hope you can follow this, I haven't posted many recipes, but these tacos were awsome!