Rinse the wolf fish under running water and dry off with kitchen roll, sprinkle with lemon.
Cook the asparagus until al dente.
Bring the fish stock to a boil and poach the fish in the fish stock. Drain the fish and place it on a pre-heated platter.
Sieve the stock, add white wine, and reduce until 1/3 of the liquid is left.
Add the butter and cheese and whip, season with salt and pepper.
Arrange the asparagus on the platter with the fish, and cover with lashings of sauce.