Peel and poach langoustines in a medium pot with half a cup of boiling water, fish sauce and salt to taste.
Remove langoustine and put aside. Add pasta and a half a cup of boiling water to the same pot. Cook until pasta is soft.
Remove the pasta and coat in finely grated Parmesan cheese.
Plate in a horizontal swirl and place langoustine on top.
Drizzle a little olive oil and carefully pour the broth in such a way that the pasta sits around it. Use a squeeze bottle (or make a tube out of paper or plastic) to submerge pearls of purée in the broth.