Grilled hearts of romaine have picked up popularity within foodie circles and restaurants worldwide in recent times. Multitudes of variations on romaine lettuce salads have been enjoyed since romaine's (kos) introduction in early egypt, but its charms have just been waiting to be discovered as a top selection for grilling recipes. Romaine's mild sweetness turns into a delightful blend of smoky goodness when seared on the grill. Be warned, not all lettuce will respond as well as romaine on the grill so substitutes will be hard to find. Though this grilled romaine lettuce recipe works best dressed with strongly flavored vinaigrettes or salty cheeses such as parmesan or grana padano, the pure, unadulterated simplicity of salt and pepper is every bit as rewarding if you want to leave out the cheese. The grilled romaine is not a dish for keeping. It should be freshly made and served immediately. Leave it lingering and the lettuce will wilt and lose flavor quickly. In the middle of winter do not despair if you are not getting the outdoor grill fired up, this recipe works very well using a cast-iron grill pan; the results are almost the same except you are not in the fresh air.