Heat the saucepan over medium heat. Add all the dried spices and dry roast, tossing around until it smells amazing, about 3-5 minutes.
Remove the pan from the heat and then add the ginger, shallots and white part of the scallions. Stir all together until you can smell their fragrance and the pan cools down a little.
Add the chicken broth and bring the pan back in the heat. Increase the heat to high and bring them to boil. Add the sugar and fish sauce. Lower the heat to medium-low, and let the stock simmer for 30 minutes.
Add the chicken breast and let it poach for 10 minutes. When the chicken is cooked all the way through, remove the chicken, put it on a separate plate and slice. Strain the broth using a mesh strainer. Discard all the herbs and spices.
In the meantime, while the broth is cooking, place the rice noodles in a large mixing bowl. Pour hot water until the noodles are fully submerged. Let it soak for 10 minutes. Drain and wash with cold water to remove the starch. Set aside. (this can be done ahead of time)
Bring the stock to boil. Taste and adjust the seasoning. It should be tasty and a little salty on the side. Drop the noodles and let them cook for a minute.