Directions

1. Place the chicken and onions in a large bowl. Cut a few slits into the chile, and add it to the bowl. Whisk together the lemon juice, mustard, garlic, 1/4 cup of the grapeseed oil, and 1 teaspoon of the salt in a small bowl; add them to the chicken mixture in the bowl, and toss to coat. Seal the bowl tightly with plastic wrap, and place it in the refrigerator for at least 3 hours and up to 12 hours.
2. Remove the chicken from the marinade, gently scraping off any onions, and transfer the chicken to a plate; set aside until room temperature, about 30 minutes. Set aside the chile, onions, and marinade until ready to use. Preheat the oven to 350°F.
3. Heat the remaining 2 tablespoons of grapeseed oil in a medium or large Dutch oven or large heavy-bottomed pot over medium-high heat. Sprinkle the chicken on both sides with pepper and the remaining 1 1/2 teaspoons salt. Working in 2 batches, place the chicken in the Dutch oven, and brown on both sides, 7 to 10 minutes per batch, turning halfway through the cooking time. Transfer the browned chicken to a clean plate.
4. Add all of the reserved onions and marinade to the Dutch oven; cook over medium-high, stirring constantly, until the onions soften and start to brown, about 5 minutes, scraping up any browned bits on the bottom of the Dutch oven. Cover the Dutch oven, and reduce the heat to medium-low. Cook, stirring every 3 to 4 minutes, until the onions start to caramelize, about 15 minutes.
5. Move the onions to 1 side of the Dutch oven, and place the chicken in the Dutch oven. Top the chicken with the onions. Add the carrots, broth, olives, and reserved chile. Increase the heat to medium-high, and bring to a simmer.
6. Cover the Dutch oven, and bake in the preheated oven until the sauce is thickened and chicken is cooked through and falling off the bone, about 1 hour, 20 minutes. Season with additional salt and pepper to taste.
7. Serve Chicken Yassa warm over Fonio.