In a small bowl, whisk together the Greek yogurt, garam masala, turmeric, cumin, sea salt, and black pepper.
Cut the chicken breast into bite-sized pieces, toss with the yogurt mixture until well coated, and marinate for 15 minutes.
Heat the ghee in a large skillet over medium-high heat.
Add the finely chopped yellow onion and sauté until softened and translucent, about 5 minutes.
Stir in the minced garlic and grated fresh ginger, cooking for 1 minute until fragrant.
Add the marinated chicken to the skillet and cook until browned on all sides, approximately 6 minutes.
Pour in the tomato puree and bring the mixture to a gentle simmer.
Reduce the heat to low, cover the skillet, and cook for 10 minutes to allow the flavors to meld.
Stir in the full-fat coconut milk to create a rich sauce and heat through for an additional 2 minutes.
Garnish with chopped fresh cilantro and serve warm.