Peel the asparagus and cook in salted water for 5 - 8 minutes until al dente. Set aside, save the asparagus water.
Make a roux out of butter and flour, deglaze with about 0.5 liters of the asparagus water and bring to the boil while stirring constantly. If the sauce is still too thick, add a little asparagus water until the sauce has the desired consistency. Simmer for 10 minutes while stirring. Carefully season with salt and lemon juice, add all the peppercorns to taste and heat the asparagus in the sauce.
New potatoes and a nice white wine also taste good.