Place the beef in a large resealable plastic bag. Add the soy sauce, brown sugar, sesame oil, ginger, black pepper, salt, garlic and grated pear and massage into the meat well. Chill and let marinate for at least 2 hours or up to overnight.
Heat a grill or grill pan until very hot. Shake off any excess marinade from the meat and grill the beef strips until desired doneness, about 30 seconds each side for rare.
Serve immediately with white rice, green leaf lettuce, Ssam Jang Sauce and sesame leaves if using. Place a small scoop of rice, a smear of Ssam Jang Sauce and a piece of beef into a lettuce leaf. Wrap and enjoy.
Mix the soy bean paste, sesame seeds, chile paste, mirin, sesame oil, garlic and spring onions together. Transfer to a small bowl and serve with kalbi or other grilled meat.
LA- or flanken-cut short ribs are ribs that are cut into slices across the bone. If you are serving the meat with bones still attached, trim the strip of bones off, then snip the meat into bite-size pieces with kitchen shears. Gnaw on the bones like a true Korean.