Wash the asparagus and cut the ends off generously. Cut the asparagus into diagonal pieces. Cook them in just under 1/2 l boiling, slightly salted water, covered with 1 pinch of sugar for about 10 minutes. Drain and collect a good 1/4 l of asparagus stock
Wash the salmon and pat dry well. Cut into cubes and sprinkle with lemon juice. Heat the butter in a pan. Fry the salmon for 5-6 minutes.
Cook the pasta in boiling salted water for about 8 minutes until al dente. Peel and finely dice onion. Season salmon with salt and pepper, remove and keep warm. Sauté onion in frying fat. Sprinkle with flour and sauté while stirring. Stir in wine, asparagus stock and milk. Bring to the boil and simmer for about 5 minutes
Season the sauce with salt and pepper. Heat asparagus and salmon in the sauce. Drain the pasta. Arrange everything and garnish with lemon