Thickened Beef Stock

WHENEVER I NEED a basic brown sauce (called a demi-glace), but do not have the time to make one, I use a thickened beef stock called a jus lié. Since my beef stock is very mild, I reduce the stock by half and add some meat glaze to heighten its flavor. To thicken the stock, I use arrowroot, potato starch, or cornstarch (in that order of preference), dissolved in a little cold water.

The tomato traditionally found in a classic demi-glace is omitted from this thickened stock, g