Rinse chicken parts, pat dry, season with salt and pepper, to taste. Heat oil (2 tablespoons) in a large stew pot or dutch oven till hot, but not smoking. Brown the chicken over medium-high heat in batches, (4-5 pieces at time) about 3 minutes per side. Once the chicken is browned, set it aside.
Pour 2 additional tablespoons of oil into the pot and add the onions, garlic and ginger. Cook, stirring, until fragrant and somewhat softened, about 3 minutes. Return chicken to pot. Add the cubed sweet potatoes, tomatoes (2 cups), cayenne pepper (3/4 teaspoon), and only 4 cups (out of 6) of chicken broth.
In a bowl, whisk the peanut butter (1 cup) with the other two cups of broth. When fully combined, pour the mixture into the stew pot. Bring the to a boil, reduce heat to a steady low simmer and cook, uncovered , for 1 hour, or until chicken is tender and falling off the bone.
Remove stew from heat. Using tongs, lift chicken pieces out of the stew, remove meat from bones and shred. You won’t need the bones for this recipe. Return shredded chicken to the stew pot. Season stew with salt and fresh pepper, to taste.
Ladle stew into shallow bowls. Garnish generously with cilantro and peanuts (optional).