Season the chicken breasts with salt and pepper, fry them in oil for a few minutes on both sides, until pale brown. In a separate frying pan, fry the onion, sweet pepper and garlic, adding the fresh tomatoes, tomato paste, coriander and the peanut butter. Add the chicken to the sauce, cover, and let cook completely until it is tender, 30 minutes at low to medium heat. Stir occasionally. Serve with Arroz con leche de coco.