Wash the chicken thighs and dry them very well. Season the chicken with sea salt, olive oil, crushed garlic, lemon juice, parsley and pepper.
Place the chicken inside a plastic bag and marinate for about twelve hours. Cut the onion and lemon into slices.
Put the chicken thighs on a rotisserie with grid; in the lower part place the chicken broth together with slices of lemon, onion and rosemary.
Preheat the oven to maximum temperature and bake the chicken thighs at that temperature for a maximum of ten minutes; if it exceeds that time the chicken can burn on the outside and raw inside.
After the first ten minutes cook on low heat, 200F for about two hours. The broth should dry. Serve the chicken with sliced onions and lemon and sea salt.