Korean Steak in Lettuce Cups

In medium bowl, stir soy sauce, sugar, oil, ginger, ground red pepper, and garlic until blended. Add beef, turning to coat with soy-sauce mixture, and marinate 15 minutes at room temperature, stirring occasionally. In nonstick 12-inch skillet, heat celery, carrots, and 1/3 cup water to boiling over medium-high heat. Cook 2 to 3 minutes or until vegetables are tender-crisp, stirring occasionally. Add beef with its marinade and cook 2 minutes or until meat just loses its pink color throughout, stirring quickly and constantly. Stir in green onions and sesame seeds, and cook 1 minute, stirring. To serve, let each person place some beef mixture on a lettuce leaf. Garnish with green-onion tops. If you like, fold sides of lettuce leaf over filling to make a package to eat out of hand.