Cut the chicken into thin and long bites and marinate them for an hour in a little soya sauce, olive oil, black pepper and lemon juice. Then drain them, roll them in breadcrumbs, the whisked eggs and breadcrumbs again and fry them to a nice tan in preheated oil.
For the sweet and sour sauce, heat the olive oil and butter and fry the finely chopped peppers. Allow to fry for 3-4 minutes and add the ketchup, with the water, lemon juice and vinegar dissolved in it. Allow the sauce to boil until the liquid has evaporated by half.
Add the sugar and let it boil for another 2-3 minutes. Thicken the sauce with the starch, dissolved with 2 tablespoons water. Combine the chicken with the sweet and sour sauce in a pot, stir it on the heat for 3-4 minutes and remove it.
Serve with a side of vegetables.