In a medium bowl, whisk together the Greek yogurt, turmeric, and 0.5 teaspoon of garam masala, then add the chicken and marinate for at least 15 minutes.
Heat the ghee in a large skillet over medium-high heat and sear the chicken until golden brown on all sides, then remove the chicken and set it aside.
In the same skillet, add the diced onion, minced ginger, and garlic, sautéing for 3-4 minutes until the onion is soft and translucent.
Stir in the tomato puree, the remaining 1 teaspoon of garam masala, cumin, sea salt, and black pepper, allowing the sauce to simmer for 5 minutes.
Pour in the coconut milk and return the seared chicken to the skillet, simmering for another 5-7 minutes until the sauce has thickened and the chicken is fully cooked.
Divide the cooked basmati rice into bowls and top with the chicken tikka masala, garnishing with fresh cilantro before serving.