In the lettuce world, Boston lettuce falls into the category of butterhead lettuces. They have small heads with leaves that seem loose when compared to harder cousins like the iceberg.
The inner leaves are practically soft as butter, giving them their name, and giving salads made with them a relatively luxurious feel. After being first identified in Europe, butterhead lettuces are now widely available in the United States.
Boston lettuce leaves are pliable and don't have stiff ribs like Romaine varieties, making them popular choices for edible wrappers. So besides the usual salads, Boston lettuce leaves are used to roll chopped chicken salad and poached shrimp for summer luncheons.
They're also used to wrap morsels of marinated grilled beef, Korean style, called bulgoki. Baskets of washed and dried leaves are served with platters of marinated meat at a Korean grilling table, with the grill set into the tabletop so diners can cook their own food and enjoy the freshest grilled dinner possible.
> Korean grilled beef (Bulgoki)
2 pounds beef sirloin, thinly sliced
1/2 cup soy sauce
1/4 cup honey or brown sugar
2 tablespoons sesame oil
1/2 teaspoon black pepper
2 tablespoons chopped garlic
1/4 cup chopped scallions (optional)
Boston or other loose-leaf lettuce leaves, for serving
Put soy sauce, sesame oil, black pepper, honey or sugar, garlic and scallions, if using, into blender or food processor. Whir until smooth.
Pour over sliced sirloin. Mix well so all meat is thoroughly coated. Marinate in refrigerator for 30 minutes to overnight.
Heat a grill, broiler or frying pan. Shake off excess marinade and cook beef until done, 1 to 2 minutes per side. Watch closely as sugary marinade will burn quickly. Crisp brown edges are good.
Bulgoki is typically served with gochujang, Korean bean-chili paste. (If you can't find it you can substitute another sweet-spicy mixture. Try equal parts hoisin sauce and a chili sauce, like sambal oelek.)
Swipe a little sauce on a lettuce leaf, wrap around grilled beef and eat.