Pepper Steak with Onions

Preparation : Mix 2 teaspoons cornstarch, soy sauce, 1 teaspoon sugar, pinch of salt and pepper; add sirloin. Marinate for 10 to 15 minutes. Drain sirloin; fry in small amount of hot oil over high heat until meat loses red color. Push to outer edge of pan. Add small amount of oil; cook onion, green peppers and celery for 5 minutes. Make paste of 2 tablespoons cornstarch and water; stir in 1 teaspoon sugar, msg and salt and pepper to taste. Add to sirloin mixture; cook stirring, until sauce is clear. Add tomatoes and green onions, remove from heat. Serve.