Add Onion and seasonings to Chicken. Moisten with a little water and cook over medium heat in a large saucepan for 15 minutes. Stir once or twice. While Chicken is cooking, mix Peanut butter with water in a bowl until smooth. Add to Chicken. Bring to a boil. Continue boiling for 30 minutes. Grind tomatoes in a blender until smooth. Add tomato pulp to soup. Simmer until Chicken is tender and oil begins to form in soup. Stir from time to time. Sprinkle with pimentos before serving. Accompany with fufu and boiled potatoes or yams. Cooking time: 1 1/2 hours.