What sauce is made by thickening brown stock with cornstarch or similar starch?

Here's how it works:

* Brown stock is made by simmering bones, vegetables, and aromatics for a long time. This creates a flavorful and rich base.

* Cornstarch or other starches are added as a thickener. When heated, the starch granules absorb liquid and swell, creating a smooth and glossy sauce.

This basic process can be further customized with different flavorings and ingredients, but the core principles remain the same.