In a bowl, combine the chicken chunks with salt, garlic powder, sweet paprika, curry powder, and Greek yogurt. Mix well until all pieces are evenly coated in spices and yogurt to enhance flavor and tenderness.
In a large skillet over medium heat, add vegetable oil and let it warm up before adding minced garlic and diced onion. Sauté until onions become translucent and garlic is fragrant but not burnt.
Once your aromatics are ready, add marinated chicken pieces to the skillet in a single layer without overcrowding them. Cook until browned on all sides.
Pour in tomato sauce along with sugar, salt, black pepper, heavy cream, cayenne pepper (if using), garam masala, and additional curry powder into the skillet with browned chicken pieces. Stir everything together until well combined.
Allow your butter chicken mixture to simmer gently on low heat for about 15-20 minutes or until it thickens slightly and all flavors meld together beautifully.
Once ready, garnish your butter chicken with freshly chopped parsley if desired and serve it hot with warm naan bread alongside steamed rice.