Wash the asparagus, cut off the woody ends. Cut the asparagus diagonally into pieces. Prepare pasta in boiling salted water according to package instructions. Bring milk and cream to the boil, thicken with sauce thickener.
Bring to the boil again. Add lemon juice, season with salt, pepper and 1 pinch of sugar. Cook the asparagus in boiling salted water for about 5 minutes, drain and drain. Meanwhile wash the salmon, dab dry and cut into pieces.
Heat the oil in a pan. Fry the salmon for 3-4 minutes while turning. Add salmon and asparagus to the sauce. Arrange noodles and sauce on plates. Garnish with lemon slices and basil.