Heat the ghee in a large skillet over medium heat until melted and shimmering.
Add the diced onion, minced ginger, and minced garlic to the skillet, sautéing for 3-4 minutes until the onion is translucent.
Add the cubed chicken breast to the pan and cook until browned on all sides, approximately 5-6 minutes.
Stir in the garam masala, turmeric, and cumin, stirring constantly for 1 minute to toast the spices and coat the chicken.
Pour in the tomato puree and bring the mixture to a gentle simmer.
Reduce heat to low, cover, and cook for 8-10 minutes until the chicken is cooked through and the sauce has thickened.
Stir in the coconut milk until the sauce is creamy and well combined, then season with sea salt.
Serve the butter chicken over the warm, cooked basmati rice and garnish with freshly chopped cilantro.