Espagnole is a base sauce made by thickening a dark stock drawn from roasted bones and vegetables with a brown roux. It is regarded as one of the five mother sauces of classic French cuisine and is the starting point for derivative sauces such as demi-glace. Despite its name, its connection to Spain is unclear, and its origin is disputed.
Where It's Used
“Prepare espagnole sauce as a dark base alongside red meat main courses.”