Cut the chicken into pieces and leave them to marinade for at least an hour in mixed soya sauce, olive oil, lemon juice, thyme, marjoram, curry and a little salt to taste. To prepare the sweet and sour sauce, first cut the two peppers into small pieces and stew in olive oil and butter for a few minutes.
Dissolve the ketchup in the water, lemon juice and vinegar and add in the peppers. Leave it to boil about 5 minutes and let the water evaporate a bit. Add the sugar, then 2-3 minutes later, condense the sauce with the starch that has been diluted in about 2 tablespoons of water.
Drain the chicken and fry it in hot oil. Immediately place it in a sealed container to brew. In a deep dish with a non-stick bottom, place the chicken, pour the sauce on and stir a few times to get it evenly seasoned.
Leave on the stove until boiled.