Heat the sesame oil in a large pot over medium heat;add the garlic and ginger, and cook for a few minutes until softened. Add the soy sauce and stir to combine.
Add the chicken stock, mushrooms and chicken. Bring to a boil and simmer for 5 minutes.
Add the Udon noodles and cook for 3-4 minutes (or according to package directions).
Stir in the green onions.
Serve and enjoy!
