Veal glace is a sauce that is used as an ingredient in many traditional dishes in French cooking. It typically consists of veal stock, along with a mixture of cooked vegetables known as espagnole. French cuisine often uses the glace as an accompaniment to meat dishes or it can be combined with other ingredients, such as cream or mushrooms, to make an even thicker or more flavorful sauce.
Veal stock is one of the main components of veal glace. French chefs tend to agree that the quality of the finished product will usually mainly depend on the quality of the veal stock that is used. The bones, along with scraps of meat still attached, are slowly simmered in liquid until a rich stock is created. The longer the veal bones and meat scraps can simmer, the more flavorful the stock will tend to be. Some chefs may not have easy access to veal to make the stock and rely on store-bought versions.
Since the veal stock requires a long cooking time, it is usually prepared far in advance of the other main component of veal glace. Espagnole is a mixture of chopped onions, carrots, and celery that are cooked in butter until the vegetables are softened. The vegetables are then mixed with tomato paste, along with a mixture of flour and butter that are cooked together until they form a paste, called a roux. The entire mixture is them simmered in water for approximately two hours or so to allow all of the flavors to blend together.
The veal glace is made by combining the veal stock and espagnole together. To maintain the correct texture, equal amount of the two mixtures are used. Once the two dishes are combined, they are heated until the liquid cooks down by half of what was there originally, which gives the mixture a concentrated flavor. The length of time it takes to reduce the glace will generally vary depending on how much liquid was used.
Although making veal glace can be a time-consuming process, it can be stored in the freezer for approximately six months. Some chefs may divide the glace into small portions prior to freezing to allow for easy defrosting in recipe-sized portions. If making a homemade version of the glace is not possible, it is typically available commercially at gourmet food stores.