Trim the bok choy, then cut into quarters vertically.
In a large skillet, heat the oil. Add the turmeric and salt and stir. After a minute, add a few drops of water, stir until the mixture becomes smooth. Add more liquid.
Place the bok choy in the skillet, cut sides down. Cover with water and bring to a gentle boil. Cover and let cook for about 15 minutes, checking occasionally to make sure the gentle boil is being maintained. If the bok choy isn't fully submerged, flip after 15 minutes. Cook for another 15 minutes.