Clean the chicken legs, wash them and put in a colander to drain.
Grate the onion head and squeeze out its juice through a cheesecloth, add it to the marinade.
Taste the marinade to check the balance between sweet-sour-spicy and adjust according to taste.
Dip the legs in the marinade and leave them in the fridge for at least 1 hour - the longer the better.
Transfer the legs to the bag, along with the marinade, as well. Tie the bag with the specialized tie and shake it slightly to distribute everything evenly.
Put it in the baking tray, into which you've poured in 1 cup water. Make 2-3 holes on top with a toothpick so it doesn't swell during baking.
Transfer the tray to a preheated 356°F (180 °C) oven (middle element with fan on) and bake about 1 hour 20 min.
Distribute thus prepared chicken into servings, garnish with the baked-sauteed vegetables and decorate with slices of green pepper.