In a bowl, combine chicken pieces with lemon juice, soy sauce, grated ginger, and minced garlic. Marinate for at least 30 minutes in the refrigerator.

Heat palm oil in a large pot or Dutch oven over medium heat. Add chopped onion and sauté until softened, about 5 minutes.

Add the marinated chicken to the pot. Brown the chicken on all sides, stirring occasionally, for about 8-10 minutes.

Stir in the chopped spinach. Cook until the spinach wilts, which should take about 3-5 minutes.

In a separate bowl, whisk together the ground peanut butter with 250 ml of water until smooth.

Pour the peanut butter mixture into the pot with the chicken and spinach. Stir well to combine.

Bring the sauce to a gentle simmer. Reduce heat to low, cover, and cook for 20-25 minutes, or until chicken is cooked through and tender.

Stir occasionally to prevent sticking. If the sauce becomes too thick, add a little more water until desired consistency is reached.

Taste and adjust seasoning if necessary. Serve hot with steamed rice or boiled plantains.