1 lb. beef flank steak
1 tbsp. cold water
1 med. onion
1/2 c. water
1/4 c. white vinegar
1 tbsp. soy sauce
2 med. tomatoes, cut into eighths
1 tbsp. cornstarch
3 tbsp. vegetable oil
1 can pineapple, drained
1/4 c. sugar
1 tbsp. instant chicken bouillon
1 med. green pepper, cut into pieces

Cut beef with grain into 2 inch strips. Cut stripes across grain into 1/8 inch slices. Mix cornstarch and 1 tablespoon cold water. Heat oil in 12 inch skillet or wok over medium heat until hot. Add beef and onion; cook and stir until beef is brown, about 3 minutes. Stir in pineapple, 1/2 cup water, the sugar, vinegar, instant bouillon and soy sauce.

Heat to boiling. Stir in cornstarch mixture. cook and stir for 1 minute. Stir in green pepper and tomatoes and cook for 1 more minute. Serve over white rice. Chicken may be substituted for beef.