Separate bok choy stems and leaves, then cut them into bite-sized pieces.

In a pot, add all ☆ ingredients and bring to a boil over medium heat. Add bok choy stems and cook until tender, then add bok choy leaves and cook until softened.

Mix the cornstarch and water to create a slurry. Add it to the pot and stir until the soup thickens. Bring to a boil, then add the beaten egg and turn off the heat. Let the residual heat cook the egg for about 1 minute, then stir gently.