Cut off the asparagus tips and blanch them in boiling salted water for 5 minutes. Use the stems for soup or stock. Drain the tips under cold running water and pat dry.
Bring at least 1.8 litres/3 pints water to the boil in a large saucepan. Add a dash of oil and a generous pinch of salt. Cook the fettucine or tagliatelle for 8—12 minutes, or according to packet instructions, until just tender.
Drain and return to the pan. Toss over a low heat with the asparagus, smoked salmon, cream, tarragon and salt and pepper until heated through.
Transfer to a warmed serving dish and garnish with wafer-thin shavings of Parmesan cheese, if liked.
Use 12 oz (375 g) mixed ceps, shiitake, and oyster mushrooms instead of the asparagus. Cut into even-sized pieces and stir-fry in 2 tablespoons olive oil for 5-7 minutes, then add to the pasta