Bring the stock and shrimp shells to a boil in a large pan. reduce the heat and simmer covered for 10 minutes. Strain the solids from the stock and return to heat.
Add shallot, garlic, lime juice, fish sauce,brown sugar, sriracha sauce and mushrooms to broth. Simmer 10 minutes
Cook noodles as directed. Add noodles to soup. Drizzle in the beaten eggs in a steady stream while stirring soup. Add the shrimp and cook 2 minutes. Remove from heat and add the bean sprouts, green onions, peanuts, and cilantro.