Prepare the Marinade: In a bowl, combine the garlic, chili flakes, basil leaves, black pepper, extra virgin olive oil, and a pinch of salt.
Marinate the Chicken: Add the chicken breasts to the marinade, ensuring they are well coated. Let them marinate for at least 30 minutes, or for best results, overnight in the refrigerator.
Grill the Chicken: Preheat your grill to medium-high heat. Grill the marinated chicken breasts until they are thoroughly cooked and have nice grill marks, about 6-7 minutes per side, depending on thickness.