Prepare the marinade by mixing half the onions, 2 tablespoons of mustard, 4 tablespoons of peanut oil and lime (or lemon) juice. Add salt and pepper. Rub chicken with the marinade and let stand several hours in refrigerator.
Preheat oven to 400F/200, on grill position. Arrange the chicken pieces on a baking sheet lined with parchment paper and roast for about 20 mins, turning chicken halfway through. All the pieces must be toasted and golden.
Heat the remaining oil in a frying pan, add the remaining onions and cook on medium heat for 5 minutes, then add the vinegar, the stock cube and the remaining mustard and garlic. Add salt and pepper.
Sauté for a few minutes over medium heat, then add a glass of water and cover. Add the chicken, jalapeño and olives and sauté for a few more minutes, stirring regularly. Then add a small glass of water and the chilies.
Bring to a boil, cover and cook on low heat for 45 mins.