Cook the pasta in boiling salted water for about 10 minutes. In the meantime peel and finely dice the onion. Cut salmon into strips. Melt the fat in a pot, fry the onion until transparent, dust with flour and sauté. While stirring, gradually deglaze with stock and cream and bring to the boil.
Season sauce with salt, pepper, sugar and lemon juice. Carefully stir in salmon. Drain noodles, quench and drain well on a sieve. Put the pasta into a greased ovenproof dish, fill in the sauce, sprinkle with parmesan and bake for 4-5 minutes in a hot grill (or alternatively in a preheated oven (electric: 250°C/ gas: level 5) for about 10 minutes. Serve garnished with dill and lemon