Wash the asparagus, cut off the woody end, peel the lower third. Halve the asparagus. Rinse meat, dab dry. Tie into shape with kitchen string. Wash lemons thoroughly and cut into slices.
Fry the meat in hot oil for about 5 minutes on each side. Then season with salt and pepper. Remove from the pan and keep warm. Stir starch with 3 tablespoons of water until smooth. Add lemon slices to the cooking fat and fry briefly.
Deglaze with stock, bring to the boil. Stir in the starch, bring to the boil again and season with stock, salt and pepper. Keep sauce warm. Cook asparagus in boiling salted water with sugar for about 8 minutes.
Bring 375 ml water to the boil with 1/2 teaspoon of salt. Pull the pot off the stove. Add milk and 20 g butter. Stir in the puree flakes with a wooden spoon and let it swell for about 1 minute. Wash chervil and chives, dab dry.
Chervil leaves finely chop, chives in fine rolls cut. Stir the herbs into the puree. Drain the asparagus and let it drain. Melt 30 g butter. Arrange meat with lemon slices, sauce, asparagus and puree.
Drizzle the mashed potatoes and asparagus with butter. Garnish with chervil as desired.