1 1/4 pounds lean, tender beef steak 1/2 medium hard pear 4-5 garlic cloves 2-inch cube fresh ginger 4 tablespoons Japanese soy sauce (shoyu) 5 medium mushrooms 2 small onions 3 scallions 1 medium carrot 2 tablespoons sesame oil 1 tablespoon roasted sesame seeds 2 1/2 tablespoons sugar Cut meat against the grain into 3- by 2-inch rectangles about 1/8-inch thick. Peel and core pear half and chop coarsely. Peel garlic, ginger; chop coarsely. Put pear, garlic, ginger, soy sauce in electric blender. Blend until smooth.
Cut mushrooms into 1/8-inch slices. Peel and thickly slice onions. Cut scallions into 2 1/2-inch lengths. Peel carrot, cut into 2 1/2-inch chunks. Cut each chunk lengthwise into 1/8-inch slices.
Put meat in a bowl. Add paste from blender, mushrooms, onions, scallions, carrot, sesame oil, sesame seeds, sugar. Mix well. Cover and marinate for 1 to 24 hours.
Set large cast-iron frying pan on high heat, and heat to nearly white-hot. Put in as many meat slices as will fit in one layer. Turn meat pieces over as soon as they brown a little. Leave meat rare, if you like, and remove as soon as ready. Cook remaining meat in same way. Add vegetables, marinade, and all meat to frying pan, cooking on high heat for a minute or so. Spoon mixture over or beside meat. Serve immediately. Serves 4. Recipe adapted from Madhur Jaffrey's `Far Eastern Cooking' (New York: Harper and Row).