Wash the chicken meat, dab dry and cut into strips. Heat oil in a pan. Fry the meat in it vigorously while turning. Season with salt and pepper. Wash the asparagus, cut off the lower woody ends.
Cut asparagus into small pieces and cook in boiling salted water for about 5 minutes. Heat pâtés in a preheated oven (E: stove 200 °C/ gas: level 3) for 10 minutes. Melt the fat in a saucepan.
Sweat flour in it. Deglaze with stock, wine and cream while stirring. Bring everything to the boil, simmer for about 3 minutes. Season to taste with salt, pepper and lemon juice. Drain the asparagus and let it drain.
Add the meat and asparagus to the sauce and warm it up. Chervil, except for something to garnish, chop roughly and fold into the ragout. Fill the asparagus ragout into the pâtés, place on plates, and add the rest of the ragout to the plates.
Garnish with lemon slices and chervil.