Recipe courtesy of The Kitchn
4 to 5 cups vegetable or chicken broth
2 whole star anise
1 stick whole cinnamon
2 large eggs
2 (7-ounce) packages fresh or frozen udon noodles
4 to 5 large bok choy leaves, sliced into ribbons
2 spring onions, thinly sliced
3 to 4 tablespoons soy sauce
Bring the chicken broth to a simmer in a medium saucepan. (The broth should be about 2 inches deep in the pan.) Add the star anise and cinnamon and simmer for 5 to 10 minutes to infuse the broth with the spices. When finished, use a slotted spoon to remove the spices.
Crack the eggs into separate measuring cups and slip them into the simmering broth, one at a time. Cook for 2 minutes, then add the noodles and bok choy. Stir very gently to submerge the noodles and bok choy, but so as not to break the eggs. Cook for another 2 minutes, until the whites of the eggs are completely set but the yolks are still loose. (Cook for an additional minute if you like your yolks set.)
Off the heat, gently stir in the soy sauce and the spring onions. Taste and add more soy sauce if necessary. Divide the soup between two bowls and eat immediately.