Wash the salmon fillet, pat dry, cut into large cubes and lightly salt.
Peel the cucumber, cut in half lengthways, core and cut into pieces. Peel and dice the onion. Wash, pat dry and chop parsley.
Bring the water for the pasta to the boil and season with salt.
Heat a tablespoon of clarified butter in a saucepan. Sauté the onion and cucumber in it. Deglaze with vegetable stock, add salt, pepper and a pinch of sugar, cook for another 2-3 minutes.
In the meantime, heat the remaining clarified butter in a coated pan and briefly fry the salmon cubes in portions all around.
Add the pasta to the boiling water and cook according to the instructions on the packet until al dente.
Add the salmon cubes, cream and mustard to the vegetables and cook for another 3 minutes. Add parsley, season the sauce to taste and bind with a sauce thickener.