Peel the asparagus and cut into 3 cm long pieces, put the asparagus tips aside.
Peel and dice the onion and sauté in butter in a large saucepan. Add the asparagus pieces and sauté briefly. Pour in the broth and simmer for about 20 minutes.
Then puree everything in the blender. Add half of the cream and bring to the boil briefly. Season with salt, pepper and lemon juice. Cut the ham into narrow strips. Let it steep in the soup for approx. 8 minutes with the asparagus tips.
In the meantime, wash the chives and cut them into small pieces. Beat the rest of the cream until stiff and fold in before serving. Place the soup on 4 plates and sprinkle with the chives.