Slice the garlic into thin pieces. Take only the white portion of the lemongrass and thinly slice it. If using chilies slice a few pieces or leave them whole , depending on your preference for heat.
Heat oil in a large stockpot and add the sliced garlic, chilies, and lemon grass. Saute for 1 minute and add add the chicken stalk to the pot. Cover and and bring it to boil.Add the fish sauce and place the chicken breast in the hot stock. Let it simmer for 15 minutes.
Heat water in another stockpot and cook the rice noodles according to package directions.
Remove the chicken from the pot, let cool for a few minutes and shred into pieces using 2 forks. Return the shredded chicken to the simmering stock.
Taste and adjust salt to taste. Slice the mushrooms and add to the soup along with a few sprigs of cilantro.
Transfer the cooked noodles to the soup mix cook for a minute and turn off the heat.
Place bean sprouts in the serving bowls. Add the hot soup on top. Serve with a side of lemon wedges and sliced chilies.
For detailed instructions go to https://oventales.com/thai-style-chicken-noodle-soup-diary-free-gf/ .