Sauce vin blanc ("white wine sauce") is a French sauce made by reducing white wine with fish, chicken, or vegetable stock and finishing it with cream or butter. It is a derivative of velouté rather than one of the five classic French mother sauces, seasoned with herbs like thyme, parsley, and bay leaf, and pairs especially well with delicate proteins such as poached or pan-seared fish, chicken, and veal.
Adding sautéed mushrooms turns it into sauce aux champignons; other kitchens swap in different wines or add a liaison of egg yolks and cream for extra richness. Similar white sauces appear elsewhere in Europe, such as Italian salsa bianco and Spanish salsa blanca, though these are not identical preparations.