I make this from time to time - it's rather good, and wanted to share it

some shrimp, peeled (or anything, really, but shrimps is tasty) -- or some thinly sliced chicken breast
2 oz of thin rice noodles (rice vermicelli)
8 cups of fish or chicken broth
1 stalk of lemongrass, cut into 2" pieces and smashed
1/4 cup thai fish sauce
2 tablespoons of chili oil
1 tablespoon lemon juice
1 tablespoon of lime juice, and 2 teaspoons of zest
1/2 pickled chile
salt and ground pepper to taste
1/3 cup of rinsed and drained canned straw mushrooms
1/4 cup fresh cilantro

cook the chicken lightly (or boil the shrimp for ~3 min, and then rinse under cold water)
in the boiling water, cook the noodles for ~2-3 min
drain, rinse under cold water, and drain

combine the broth with the lemongrass, fish sauce, chile oil, lemon juice, lime juice and zest, and pickled chile. Bring to a simmer and cook for ~10 min. Remove the lemongrass.

Put the shrimp or lightly cooked chicken, noodles, mushrooms, and cilantro in your bowl and pour the soup over it.

hello Shack, let me warmly welcome you! oh, and that soup looks lovely..nice one