Prepare a clear brown veal stock. Prepare all the necessary ingredients for the binding.
2
Bring the stock to a boiling point.
3
Dilute the potato flour or in a bowl with white wine or Madera.
4
Add the white mushrooms and chervil and tarragon bunch to the brown stock. Dissolve the potato flour or cornstarch in a bowl with the white wine or Madera. Pour gradually the cornstarch on the boiling stock, whisking, to bind it as you want. Let boil and over moderate heat, frequently skimming, for an hour.
5
Filter through a .
6
Check the binding by dipping a spoon in the stock. It must be evenly . Cool down quickly and keep refrigerated for 48 hours maximum.