According to Agnes Heringer's recipe at rec.food.cooking, the best lecsó is made with sweet yellow Hungarian peppers, which are in season August–October which is also when field tomatoes are at their best. Other recipes suggest using both the bell pepper and banana pepper as alternatives.
There is a large variety of lecsós, the base of all being a mixture of tomatoes and peppers (preferably both sweet and hot), onions, spiced with salt, sugar, a fair amount of red paprika powder, often garlic. Some may use bay leaf, ground black pepper or thyme. To make the perfect lecsó base, one must render the lard from the smoked bacon (if that is used instead of oil, which is also common), and fry the onion slices until the edges become slightly brownish. Next the pepper slices must be added and fried until crisp and the tomatoes come last (because they are very juicy and if added first, they would soak the onions and pepper). One lecsó type is made with potatoes, an other is with cooked rice or egg barley called tarhonya (a kimd of large Hungarian couscous). It is possible to make lecsó with green tomatoes, cold lecsó ih aspic or serve the warm dish with sour cream, or in a pancake, as a filling. Some recipes are with meat, sausage (called "kolbász" such as lecsókolbász, made specifically for this purpose, or Debrecener sausage) bacon or smoked pork chops, liver, sliced hot dog sausages, some are decorated with hard boiled egg slices or thickened with beaten eggs, even cabbage or pumpkin are added sometimes. If meat is added, it may be added first, and fried with the onions and pepper slices. Some people eat lecsó with sugar icing on top. Lecsó, like its French semi-counterpart ratatouille, often stand alone as a lunch dish. Plain lecso can be served as a side dish accompanying various main dishes, for example meat stews like csirke paprikás and pörkölt or roasted chicken, pheasant, pork, beef or Eszterhazy steak. It is widely known in Hungary that the best lecsó is made on open fire, in a "bogrács" (a cauldron), a Hungarian style barbecue. In Hungary the dish is very popular, and even has its own festivals, e.g. in Zsámbok or Vác.
In Germany, Lecsó is referred to as Letscho and often used as the primary ingredient of a sauce that is used with many different meals. It is usually made of tomatoes, peppers, and onions among other regional additions.
In Poland, Lecsó (called Leczo) is usually made from red pepper, courgette, tomatoes, onion and garlic, sausage, spiced with powdered chilli pepper. In Poland Leczo should be served hot and spicy. It probably came to Poland from Hungary.