2 tsp cornstarch or potato flour
4 tbsp water
4 tbsp pineapple juice
3 tbsp rice vinegar or white wine vinegar
pinch of salt
4 tbsp sugar
2 tsp Chinese light soy sauce
1 tsp Worcestershire sauce
2 tbsp tomato ketchup ("Heinz")

Place the cornstarch or potato flour in a bowl and mix in the water and the pineapple juice. Add the rest of the ingredients and stir until well blended. Store the sauce tightly covered in refrigerator. Use the sauce to prepare Chinese-type stir-fry dishes, like the sweet-and-sour pork stir-fry.
Makes about 200 ml of sauce.

Recipe source: adapted from "Hapanimelä possu", So, Yan-kit (1998) Klassinen kiinalainen keittiö. Trans. Vuokko Tarpila. Porvoo: WSOY.