Fresh tender herbs (such as Thai basil, cilantro, and/or mint)
Freshly ground black pepper
Chili oil and lime wedges (for serving)
Directions
Toast cloves, cardamom, star anise, chiles, cinnamon, and peppercorns in a large pot over medium heat, tossing often, until fragrant, about 2 minutes. Add cilantro, shallots, garlic, lemongrass, ginger, broth, and fish sauce and bring to a boil. Reduce heat; simmer until flavors meld, 1–1 1/2 hours. Strain into a large bowl, pressing on solids. Return broth to pot; season with salt and pepper.
Pulse cashews in a food processor until very finely ground. Add shallot, chile, lemongrass, ginger, brown sugar, and shrimp paste; process until smooth. Heat oil in a small skillet over medium and cook paste, stirring, until beginning to brown, about 2 minutes.
Cook noodles according to package directions. Drain; rinse under cold water. Bring broth to a simmer, add shrimp, and cook until cooked through, about 2 minutes. Divide noodles among bowls. Add 2 Tbsp. paste to each and ladle broth over; stir to incorporate paste. Top with shrimp, sprouts, scallions, and herbs; season with pepper. Serve with chili oil and lime wedges alongside.
