Glace de Viande
This takes some time to prepare but it is abolutely basic to a good French kitchen, or a Frugal one for that matter
Gently boil down the brown stock until there are about 2 cups remaining. This will require changing pans once. The results will dark and thick, like molasses. Cool, and place in the refrigerator, Then cut into little blocks, dust each with cornstarch, cover, and refrigerate. Use for flavoring and coloring soups, gravies, and sauces.
Makes 2 cups.