Peel and wash the celery and cut into 1/2 cm thick slices. Steam in boiling salted water for approx. 5 minutes, drain and cut out flowers as desired (use leftovers e.g. for a soup).
Clean and wash the spring onions. Rub the mushrooms with kitchen paper, unscrew the stalk. Cut mushrooms and onions finely. Peel garlic and press it through the garlic press. Heat 10 g fat in a pot.
Fry the mushrooms, onions and garlic for 3-5 minutes. Season with salt and pepper and let it cool down. For the duchess potatoes boil 300 ml water and 1 level teaspoon of salt. Add milk and stir in the puree flakes.
After 1 minute stir again and season with nutmeg. Pour into a piping bag with star-shaped spout and squirt about 12 tuffs onto a baking tray covered with baking paper. Bake in a preheated oven (electric: 200 °C/ gas: level 3) for 5-8 minutes.
Flatten the veal cutlet a little. Season with lemon pepper and cover with 1 slice of ham. Add the mushroom filling and stick together with a toothpick. Heat clarified butter in a frying pan and fry the escalopes for 4-5 minutes while turning.
Remove, keep warm. Deglaze gravy with stock and Noilly Prat and bring to the boil. Stir cornflour in a little water until smooth and thicken the sauce. Bring to the boil again and season with salt and pepper.
Put schnitzel in the hot sauce. Heat the remaining fat in a pan and fry the celery slices until golden brown. Season with salt and pepper. Arrange schnitzel with sauce, celery flowers and duchess potatoes.
Garnish with parsley.