In a large bowl, combine chicken, onions, minced chili pepper, lemon juice, and Dijon mustard (if using).

Mix well, cover, and refrigerate for at least 4 hours, or preferably overnight, to marinate.

Remove the chicken pieces from the marinade and pat them dry.

Grill, broil, or sauté the chicken until well browned and cooked through. Set aside.

Heat the peanut or vegetable oil in a large pot over medium heat.

Remove the onions from the marinade and add them to the pot.

Sauté the onions for 8-10 minutes, until they are wilted and starting to brown.

Add the remaining marinade to the pot with the onions.

Add the browned chicken pieces to the pot.

Reduce the heat to medium-low, cover, and simmer for 30-40 minutes, or until the chicken is cooked through and tender.

Adjust seasoning to taste.

Serve hot with rice, fufu, or couscous.