The chicken legs need to marinate overnight. Wash the chicken legs and cut them as desired.
Chop the onion heads into crescents and mix them with the salt, black pepper, soy sauce and olive oil.
Pour this over the chicken legs and leave them for 12 hours to take in the spices well. It's good to put foil or other cover over the container they're marinating in.
Before you put the chicken legs to bake, put a cube of butter under their skin. Put them with the onions and 2 cups water in the oven dish you're going to be baking in.
Bake for 40 min. under foil at 392°F (200 °C). Remove the foil and crisp them for another 10 min. You can make a garnish separately.