Cut the undercut beef into I inch strips. Sprinkle with salt and pepper and leave for 2-3 hours
Heat 2tbsps of oil in a non stick pan. Fry the beef strips, turning once, until brown, about 1 minute per side.
Now add 1 cup stock .When it begins to boil stir in the corn flour paste and cook until thick.
Stir in 1tbsp soya sauce, 2tbsp brown sugar, 1tbsp vinegar, 1 cup pineapple pieces, 2 diced caspciums, 2 chopped tomatoes and 4 large green chilies.
Mix well and turn the flame off