Cook the tagliatelle al dente. In the meantime, reduce the cream, Noilly Prat and 1 sprig of dill in a small saucepan until creamy. Remove the dill again and season the sauce well with salt, cayenne pepper and pepper.
Cut the smoked salmon into strips and mix with the remaining, finely chopped dill into the sauce.
Drain the tagliatelle in a sieve, drain well and place in a preheated bowl or spread on pasta plates. Mix in the salmon-cream sauce and serve immediately.