1 1/2 pounds boned, skinned chicken breasts, rinsed
2 1/2 quarts fat-skimmed chicken broth
1/3 cup peeled garlic cloves
1 cup sliced shallots
1/4 cup salted, roasted macadamia nuts or blanched almonds
6 thin slices (the size of a quarter) fresh galangal or fresh ginger
1 teaspoon ground turmeric
1 tablespoon cooking oil
1 stalk (12 to 15 in.) fresh lemon grass or 3 strips (1/2 by 4 in.)
lemon peel, yellow part only
4 to 6 ounces dried bean thread noodles (saifun)
Salt and pepper to taste
3 cups finely shredded cabbage
3 cups bean sprouts, rinsed and drained
1 cup thinly sliced green onions, including tops
1 cup diced Roma tomatoes
1 cup chopped fresh cilantro
4 hard-cooked large eggs, shelled and cut into wedges
2 cups potato chips or shrimp chips (optional)
1/2 cup fried shallots
Lime wedges
Chili sambal, Asian red chili paste, or minced fresh hot chilies
In a food processor, combine garlic, sliced shallots, macadamia nuts, galangal, and turmeric. Whirl mixture to a paste, scraping container sides as needed. (Or chop ingredients with a knife, then whirl in a blender to a paste.)
In a 5- to 6-quart pan over high heat, stir the paste and the oil until mixture barely begins to brown, about 3 minutes. Stir in broth, cover, and bring to a boil.
Meanwhile, trim stem end and any tough leaves off lemon grass and pull off coarse outer layer. Crush stalk with the back of a knife, then cut into 3-inch pieces. Add to broth.
Add chicken breasts to broth. Cover, bring to a boil, then reduce heat to low and simmer until the breasts are no longer pink in center of thickest part (cut to test), 15 to 20 minutes.
Lift out chicken and let cool at least 10 minutes. Skim fat from broth.
In a bowl, pour 5 cups hot water over bean thread noodles. Let stand until the noodles are tender to bite, about 5 minutes; drain. Snip through noodles with scissors to make shorter strands.
Season broth with salt and pepper to taste. Return to a boil over high heat.
Tear the chicken into shreds. In individual small bowls, mound shredded chicken, bean thread noodles, cabbage, bean sprouts, green onions, tomatoes, cilantro, egg wedges, fried shallots, lime wedges, and chili sambal. Pour hot broth into a tureen or pitcher.