Marinate the hearts: in a deep bowl, mix the hearts with soy sauce, olive oil, salt, paprika, ground black pepper and garlic, chopped with a knife or passed through a press. Leave to marinate for 2 hours.
Meanwhile, remove the stalk and seeds from the bell pepper and cut into small cubes. Cut the onion into half rings and the carrot into strips.
Heat a frying pan with vegetable oil. Fry the pepper, carrot and onion for 5 minutes. Then add the chicken hearts. Fry, stirring every 3 minutes. Then cover the pan with a lid and simmer for 10-15 minutes on low heat until done.