Peel and chop the onion and garlic.
Heat the oil in a large skillet over medium-high heat. Add the chopped garlic and onion. Cook for about 8 minutes until fragrant.
While the onion and garlic cook, rinse the bok choy and cut off the ends of the stems. Then, chop each into bite-sized pieces.
On a separate cutting board, cut the chicken into bite-sized pieces as well.
Toss the bok choy into the onion and garlic mix and stir fry for 1–2 minutes until slightly tender. Then spoon this mix onto a plate and set aside.
Add the butter to the same skillet (or wok) and add the chicken in. Then, toss on the spices. Stir well and cook for 2 minutes. Then, flip chicken pieces over and cook another 2 minutes.
Pour in the coconut milk and simmer 1 minute.
Add the bok choy, onion, and garlic mixture into the pan with the chicken in spiced coconut milk and stir well.
Season with salt and pepper to taste.
Serve hot, optionally topped with red pepper flakes and chopped cilantro or parsley leaves.