Cut beef into very thin slices. Cut carrots diagonally into thin slices. Cut spring onions and onions into thin rings. Purée nashi pear and garlic together in a blender.
In a bowl, mix soy sauce, brown sugar, honey, sesame oil, the puréed garlic-pear mixture, sake, rice vinegar, and Korean chili powder.
In a large bowl, combine beef, carrots, spring onions, and onions. Pour marinade over and mix well. Refrigerate for 2-3 hours.
Heat a grill pan over medium-high heat. Cook the beef and vegetables for 2-3 minutes, stirring occasionally, until the beef is cooked through.