Wash the herbs, dab dry and chop. Stir the sauce powder into 200 ml cold asparagus stock. Bring to the boil briefly while stirring. Switch off the stove. Cut the butter into small pieces and gradually fold them in.
Remove the pot from the heat and stir in the chopped herbs. Wash and peel the asparagus and cut off the woody ends. Wash and dry lemon, cut in half and cut off 1 slice. Cook the asparagus in boiling salted water with sugar and the lemon for 15 minutes until al dente.
Meanwhile wash the meat and pat dry. Beat the egg in a deep plate and whisk. Turn meat first in flour, then in egg and finally in breadcrumbs. Remove asparagus from the pot, drain and place in a greased large casserole dish or 4 small moulds.
Spread the hollandaise sauce over the asparagus. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 15 minutes. Heat the oil in portions in a pan and fry the escalopes in 2 portions until golden brown.
Cut the rest of the lemon into slices. Garnish cutlets with lemon slices and asparagus with tarragon.