Wash, dry and dice the meat. Mix starch and soy sauce. Mix with the meat and leave to stand for 5-10 minutes
Peel and finely chop the onion. Clean and wash the mushrooms and leek. Halve mushrooms and cut leek into rings. Drain the pineapple, collect the juice
Drain the meat and collect the marinade. Heat the oil in a wok (or a large pan). Fry the meat in it until brown all around. Season with pepper and possibly salt and remove
Fry the onion, leek, mushrooms and pineapple in the frying fat for approx. 5 minutes. Deglaze with stock and marinade. Bring to the boil and add approx. 6 tbsp. pineapple juice, ketchup and vinegar. Season to taste with soy sauce, pepper, sugar and possibly sherry. Add meat and heat. Wash, quarter, seed and dice the tomato. Sprinkle the pan dish with the tomato and serve. Serve with rice, e.g. basmati