Glace de John Spottiswood

A glace is a meat or fish stock that's been cooked for many, many hours until it's thick and rich with flavor. French cooks add dollops of it to their sauces at the last minute to thicken them and boost their flavor. You can make a glace yourself or buy it ready-made, but count on paying dearly with either time or money. There are several varieties, including glace de viande (also called meat glace or meat jelly), glace de poisson ( fish glace), glace de poulet ( chicken glace), and glace de veau ( veal glace). A demi-glace is made the same way as a glace, but it's not as thick.