01 - Generously season both sides of each chicken breast with salt and black pepper, ensuring even coverage for maximum flavor penetration.
02 - Place the seasoned chicken breasts in a single layer at the bottom of your slow cooker, avoiding overlap for uniform cooking.
03 - In a large mixing bowl, combine crushed tomatoes, diced tomatoes, chopped onion, minced garlic, tomato paste, oregano, thyme, sugar, red pepper flakes, and olive oil. Mix thoroughly until all ingredients are well incorporated.
04 - Pour the tomato mixture evenly over the chicken breasts, ensuring each piece is well-coated with the aromatic sauce.
05 - Cover and cook on LOW setting for 6 hours or HIGH setting for 4 hours, until chicken reaches internal temperature of 165°F and becomes fork-tender.
06 - During the final 30 minutes of cooking, stir in the chopped fresh basil and heavy cream (if using) to create a rich, velvety sauce consistency.
07 - Taste the sauce and add additional salt or pepper if desired to balance the flavors.
08 - Plate the chicken with generous sauce, garnish with additional fresh basil leaves and grated Parmesan. Accompany with rice, pasta, or crusty bread to soak up the flavorful sauce.