Dice the chicken breast into bite-sized pieces and season evenly with sea salt and black pepper.
Heat the ghee in a large skillet over medium-high heat until melted and shimmering.
Add the chicken to the skillet and sear until golden brown on all sides, then remove the chicken and set it aside on a plate.
In the same skillet, add the finely diced onion, minced garlic, and grated ginger, sautéing until the onion is translucent and fragrant.
Stir in the garam masala, turmeric, and cumin, allowing the spices to toast for about 30 seconds to release their oils.
Pour in the tomato puree and full-fat coconut milk, whisking the mixture until it forms a smooth, orange sauce.
Return the seared chicken to the skillet, reduce the heat to low, and simmer for 10 minutes to allow the flavors to meld and the chicken to cook through.
While the chicken simmers, lightly steam or sauté the cauliflower rice until tender.
Serve the spiced butter chicken over the cauliflower rice, garnishing with fresh herbs if desired.