Rinse veal and simmer over low heat for about 1 hour in 1/2 liter (approximately 2 cups) of water, wine, soup vegetables and spices.
Rinse and mince mushrooms, then sprinkle with lemon juice. Heat butter in a pan and sauté mushrooms briefly. Remove veal from broth, pat dry and cut into cubes. Reduce broth to 1/4 liter (approximately 1 cup) and pour through a sieve. Add cream and boil again. Add veal and mushrooms to pot. Whisk egg yolk with a little broth, then fold into sauce. Season with salt and pepper.
Briefly heat puff pastry in a warm oven.
Plate pastries and smother with veal sauce. Serve garnished with basil and coriander leaves.