To a large pot, add chicken thighs, chicken broth, water, rock sugar, turmeric powder, ginger, onion, and green onion whites. Simmer for 20 minutes or until chicken is cooked through.
While the chicken is simmering, add the garlic to a food processor and pulse until finely chopped.
To a pan over low heat, add neutral oil. Once it starts lightly smoking, add the garlic and fry until lightly golden.
Drain the fried garlic through a fine mesh sieve over a heat-safe bowl. Allow the garlic to crisp up and then add it back into the garlic oil. Set aside.
To the same pan, add more neutral oil. Add sliced shallots and fry until lightly golden. Drain through a fine mesh sieve and set aside.
Bring a separate pot of water to a boil. Add bean thread noodles and cook until softened and translucent. Drain, rinse and set aside.
Once the chicken is cooked through, remove onion and ginger from the pot. Skim off any impurities in the broth. Season the broth with fish sauce and salt to taste.
Remove the chicken, shred it and set aside.
To assemble, add cooked noodles to a bowl with shredded chicken. Ladle the broth over top and garnish with scallion greens, cilantro, freshly cracked black pepper, fried shallots, and fried garlic with garlic oil.