Rinse the basmati rice under cold water until clear, then combine with 0.5 cup water in a small pot, bring to a boil, cover, and simmer for 15 minutes.
Cut the chicken breast into 1-inch cubes and season evenly with the sea salt and black pepper.
Melt the ghee in a large skillet over medium-high heat and sear the chicken cubes until golden brown on all sides.
Add the finely diced yellow onion to the skillet and sauté for 3 minutes until translucent.
Stir in the minced garlic and grated fresh ginger, cooking for another 60 seconds until highly fragrant.
Add the garam masala and turmeric to the pan, stirring constantly for 30 seconds to toast the spices without burning.
Pour in the tomato puree and stir to combine, reducing the heat to medium-low and simmering for 8 to 10 minutes.
Stir in the full-fat coconut milk to finish the sauce, allowing it to thicken slightly for 2 minutes.
Fluff the cooked rice with a fork and plate it alongside the butter chicken, garnishing with chopped fresh cilantro.