1. 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.
2. 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.
3. 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.
4. For the sauce, 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.