Preheat the oven to 350F/180C.
Brown salted chicken breasts in 1 tbsp of olive oil in a large, deep pan for approximately 5 minutes over medium heat on each side. They will not be cooked all the way through. Remove to a separate plate and set aside.
To the same pan add onions and saute for 5 minutes, then add garlic and cook for a minute longer, then add all the spices, return the chicken to the pan, add chicken stock, preserved lemons, olives and butternut squash, lightly stir and bring to a boil.
Then cover it with a lid and cook in the preheated oven for 20 minutes, then uncover and cook for 15 minutes longer. Do not overcook as chicken breasts will become dry.
Serve with rice or couscous.