Bring a large saucepan of salted water to the boil and cook the tagliatelle for a few minutes until al dente. Drain and toss immediately with the olive oil and some seasoning.
Add the sun-dried tomatoes and smoked salmon trimmings and toss well again. Spoon onto serving plates and garnish with the chervil leaves and Gruyere before serving.
*costings based on leftovers.