2 tablespoons coriander seeds
1 teaspoon black peppercorns
1 teaspoon cumin seeds
1 teaspoon fennel seeds
1/4 teaspoon ground turmeric
5 to 8 dried arbol chiles, stemmed
2 lemongrass stalks
3 tablespoons vegetable oil
1 pound boned, skinned chicken thighs, cubed
1 teaspoon shrimp paste*
3 large shallots, thinly sliced
1 can (13.5 oz.) coconut milk
1 qt. reduced-sodium chicken broth
2 teaspoons sugar
3 teaspoons kosher salt
1 cinnamon stick
6 ounces mung bean sprouts, rinsed
8 ounces wide rice noodles
1/3 cup fresh mint leaves, torn
1/3 cup fresh cilantro leaves, torn
Sambal oelek chili paste*
1. Grind coriander, peppercorns, cumin, fennel, cloves, turmeric, and chiles coarsely in a spice grinder. Peel tough outer layers from lemongrass, then mash core with a meat mallet or small, heavy frying pan.
2. Heat oil in a large pot over medium heat. Add chicken, shrimp paste, shallots, and reserved spices and cook, stirring constantly, until fragrant, 2 minutes.
3. Pour in coconut milk, broth, sugar, and salt; add cinnamon and lemongrass. Bring to a boil, then simmer, covered, 20 minutes.
4. Boil bean sprouts in a large pot of boiling water until softened, 2 minutes. Transfer sprouts to a bowl. Add noodles to pot and cook until firm, 4 minutes. Drain; rinse well.
5. Divide sprouts and noodles among 6 bowls. Ladle in soup (remove cinnamon and lemongrass) and top with mint and cilantro. Serve with limes and sambal.