Cut the chicken breast into bite-sized pieces and place them in a small bowl.
Toss the chicken with the Greek yogurt, half of the garam masala, and all of the turmeric until evenly coated; let marinate for 10 minutes.
Heat the ghee in a large skillet over medium-high heat.
Add the finely diced yellow onion to the skillet and sauté for 5 minutes until soft and translucent.
Stir in the minced garlic and grated fresh ginger, cooking for 1 minute until fragrant.
Add the marinated chicken to the skillet and cook for 4-5 minutes, browning the pieces on all sides.
Pour in the tomato puree, the remaining garam masala, sea salt, and black pepper.
Reduce the heat to low, cover the skillet, and simmer for 10 minutes until the chicken is fully cooked.
Stir in the full-fat coconut milk to finish the sauce with a rich, creamy consistency.
Serve the chicken and sauce over the warmed cooked basmati rice and garnish with chopped fresh cilantro.